diff --git a/.quixos-subtree-source.json b/.quixos-subtree-source.json
index fb594f9..772f023 100644
--- a/.quixos-subtree-source.json
+++ b/.quixos-subtree-source.json
@@ -1,7 +1,7 @@
 {
   "version": 1,
-  "sourceRepo": "https://gitea-external.egads.tutti.syntaxblitz.net/quixos/quixos",
-  "sourceCommit": "8014b4ba717313e1b494c59a8e2781df58bf9a85",
+  "sourceRepo": "https://gitea.internal.quixos.org/quixos/quixos.git",
+  "sourceCommit": "e4393946ba63cfef75580f6aa6ba840035e7d43c",
   "sourcePath": "quixos-protocol",
   "exportName": "quixos-protocol",
   "mirrorRemote": "https://gitea-external.egads.tutti.syntaxblitz.net/quixos/quixos-protocol.git"
diff --git a/nix/checked-candidate.nix b/nix/checked-candidate.nix
index 4ccb7a6..5af96c9 100644
--- a/nix/checked-candidate.nix
+++ b/nix/checked-candidate.nix
@@ -7,6 +7,7 @@
   generator,
   contractOnly ? false,
   workspaceId ? null,
+  platformSourceJSON ? null,
   system ? builtins.currentSystem,
 }:
 let
@@ -71,9 +72,21 @@ let
     else
       { };
   execution = (configuration.backend or "typescript") == "execution";
-  runtime = builtins.getFlake (
-    "git+${root.lock.quixos.repository}?rev=${root.lock.quixos.commit}&ref=refs/tags/quixos-reachability/${root.lock.quixos.commit}"
-  );
+  platformSource = if platformSourceJSON == null then null else builtins.fromJSON platformSourceJSON;
+  runtime =
+    if platformSource == null then
+      builtins.getFlake (
+        "git+${root.lock.quixos.repository}?rev=${root.lock.quixos.commit}&ref=refs/tags/quixos-reachability/${root.lock.quixos.commit}"
+      )
+    else
+      assert platformSource.repository == root.lock.quixos.repository;
+      assert platformSource.commit == root.lock.quixos.commit;
+      # getFlake accepts a context-free flake reference. storePath first checks
+      # presence; the resulting flake retains its immutable source as an input.
+      # Dropping string context here does not permit an authored mutable path.
+      builtins.getFlake (
+        builtins.unsafeDiscardStringContext "path:${builtins.storePath platformSource.directory}"
+      );
   runtimePackages = runtime.packages.${system};
   resourceClosure =
     includeBuild: node:
diff --git a/src/capability-language/checked-build.ts b/src/capability-language/checked-build.ts
index e7d21a0..922079d 100644
--- a/src/capability-language/checked-build.ts
+++ b/src/capability-language/checked-build.ts
@@ -113,6 +113,7 @@ export async function buildImmutableCandidate(
   contractOnly = false,
   observe?: (phase: "nixEvaluationMs" | "nixBuildMs", ms: number) => void,
   workspaceId?: string,
+  platformSource?: { repository: string; commit: string; directory: string },
 ): Promise<string> {
   if (workspaceId !== undefined && (kind !== "workspace" || !/^[a-zA-Z0-9][a-zA-Z0-9:._-]{0,255}$/.test(workspaceId)))
     throw new Error("Instance binding requires a valid Workspace identity and a Workspace root");
@@ -121,6 +122,13 @@ export async function buildImmutableCandidate(
   const url = new URL(source.repository);
   if (url.protocol !== "https:" || url.username || url.password || url.search || url.hash)
     throw new Error("Candidate origin must be credential-free HTTPS");
+  if (
+    platformSource &&
+    (Object.keys(platformSource).sort().join(",") !== "commit,directory,repository" ||
+      !/^[a-f0-9]{40}$/.test(platformSource.commit) ||
+      !/^\/nix\/store\/[a-z0-9]{32}-[^/\s]+$/.test(platformSource.directory))
+  )
+    throw Error("Invalid immutable platform source input");
   const generator =
     process.env.QUIXOS_CHECK_GENERATOR ?? path.resolve(path.dirname(fileURLToPath(import.meta.url)), "../..");
   if (!/^\/nix\/store\/[^/]+$/.test(generator)) throw new Error("Use the installed Quixos checker");
@@ -204,6 +212,7 @@ export async function buildImmutableCandidate(
         "contractOnly",
         contractOnly ? "true" : "false",
         ...(workspaceId === undefined ? [] : ["--argstr", "workspaceId", workspaceId]),
+        ...(platformSource ? ["--argstr", "platformSourceJSON", JSON.stringify(platformSource)] : []),
         "--add-root",
         gcRoot,
         "--indirect",
diff --git a/src/capability-language/development-sources.ts b/src/capability-language/development-sources.ts
index 97e8d26..e6d540a 100644
--- a/src/capability-language/development-sources.ts
+++ b/src/capability-language/development-sources.ts
@@ -16,8 +16,11 @@ export async function prepareDevelopmentSources(options: {
   directory: string;
   cacheDirectory: string;
   locations?: Record<string, string>;
+  workspaceId?: string;
 }) {
   const source = workspaceSourcePin(options.source);
+  if (options.workspaceId !== undefined && !/^[0-9a-f]{8}-(?:[0-9a-f]{4}-){3}[0-9a-f]{12}$/.test(options.workspaceId))
+    throw Error("Development source binding requires a Workspace UUID");
   const destination = path.resolve(options.directory);
   const cache = path.resolve(options.cacheDirectory);
   if (cache === destination || cache.startsWith(destination + path.sep))
@@ -43,7 +46,8 @@ export async function prepareDevelopmentSources(options: {
   const parent = path.dirname(destination);
   await mkdir(parent, { recursive: true });
   const staging = await mkdtemp(path.join(parent, ".development-sources-"));
-  const workspaceId = randomUUID();
+  // This local association does not create or grant access to a hosted Graph.
+  const workspaceId = options.workspaceId ?? randomUUID();
   try {
     const resources = [];
     for (const entry of closure.resources) {
diff --git a/src/capability-language/file-lock.ts b/src/capability-language/file-lock.ts
index a1419ba..2a27ece 100644
--- a/src/capability-language/file-lock.ts
+++ b/src/capability-language/file-lock.ts
@@ -1,14 +1,19 @@
 import { spawn } from "node:child_process";
 
+export class FileLockBusyError extends Error {}
+
 /** Kernel-owned lock: a crashed coordinator cannot leave a stale ownership file.
  * The persistent file is just an inode; EOF releases the helper's lock. */
-export async function withFileLock<T>(filename: string, work: () => Promise<T>): Promise<T> {
+export async function withFileLock<T>(
+  filename: string,
+  work: () => Promise<T>,
+  { nonblocking = false }: { nonblocking?: boolean } = {},
+): Promise<T> {
   const child = spawn(
     "flock",
     [
       "--exclusive",
-      "--timeout",
-      "120",
+      ...(nonblocking ? ["--nonblock"] : ["--timeout", "120"]),
       "--conflict-exit-code",
       "75",
       filename,
@@ -32,15 +37,17 @@ export async function withFileLock<T>(filename: string, work: () => Promise<T>):
     await new Promise<void>((resolve, reject) => {
       let output = "";
       child.once("error", reject);
-      child.once("exit", (code) =>
+      child.once("exit", (code) => {
         reject(
-          new Error(
-            code === 75
-              ? "Timed out after 120 seconds waiting for another authoring command; inspect that command before retrying"
-              : `Cannot acquire authoring lock: ${diagnostics}`,
-          ),
-        ),
-      );
+          code === 75
+            ? new FileLockBusyError(
+                nonblocking
+                  ? "Another process owns this lock"
+                  : "Timed out after 120 seconds waiting for another authoring command; inspect that command before retrying",
+              )
+            : new Error(`Cannot acquire authoring lock: ${diagnostics}`),
+        );
+      });
       child.stdout.on("data", (chunk) => {
         output += chunk;
         if (output.includes("locked\n")) resolve();
diff --git a/src/capability-language/source-check-driver.ts b/src/capability-language/source-check-driver.ts
index 4a4169a..e627287 100644
--- a/src/capability-language/source-check-driver.ts
+++ b/src/capability-language/source-check-driver.ts
@@ -6,5 +6,13 @@ const [repository, commit, log, workspaceId] = process.argv.slice(2);
 if (!repository || !commit || !log || !workspaceId || process.argv.length !== 6)
   throw Error("source-check-driver REPOSITORY COMMIT LOG WORKSPACE_ID");
 process.stdout.write(
-  (await buildImmutableCandidate({ repository, commit }, "workspace", log, false, undefined, workspaceId)) + "\n",
+  (await buildImmutableCandidate(
+    { repository, commit },
+    "workspace",
+    log,
+    false,
+    undefined,
+    workspaceId,
+    process.env.QUIXOS_CHECK_PLATFORM_SOURCE ? JSON.parse(process.env.QUIXOS_CHECK_PLATFORM_SOURCE) : undefined,
+  )) + "\n",
 );
diff --git a/src/capability-language/tool-cli.ts b/src/capability-language/tool-cli.ts
index 41a382d..7de8d1b 100644
--- a/src/capability-language/tool-cli.ts
+++ b/src/capability-language/tool-cli.ts
@@ -73,7 +73,7 @@ const main = async () => {
           "--dir",
           ...(args[1] !== "restore" ? ["--locations"] : []),
           ...(args[1] === "checkout" ? ["--repository-prefix"] : []),
-          ...(args[1] === "develop" ? ["--cache"] : []),
+          ...(args[1] === "develop" ? ["--cache", "--workspace-id"] : []),
           ...(args[1] === "backup" ? ["--output"] : []),
         ].includes(args[i]) ||
         !args[i + 1] ||
@@ -100,7 +100,11 @@ const main = async () => {
     if (args[1] === "develop") {
       if (!flags.get("--cache")) throw Error("source develop requires --cache DIRECTORY");
       const { prepareDevelopmentSources } = await import("./development-sources.js");
-      result = await prepareDevelopmentSources({ ...options, cacheDirectory: path.resolve(flags.get("--cache")!) });
+      result = await prepareDevelopmentSources({
+        ...options,
+        cacheDirectory: path.resolve(flags.get("--cache")!),
+        ...(flags.has("--workspace-id") ? { workspaceId: flags.get("--workspace-id")! } : {}),
+      });
     } else if (args[1] === "backup") {
       if (!flags.get("--output")) throw Error("source backup requires --output DIRECTORY");
       const { backupWorkspaceSources } = await import("./source-backup.js");
diff --git a/src/capability-model/evolution.ts b/src/capability-model/evolution.ts
index 96d18b1..f6ec15a 100644
--- a/src/capability-model/evolution.ts
+++ b/src/capability-model/evolution.ts
@@ -1,4 +1,5 @@
 import { createHash } from "node:crypto";
+import { setImmediate } from "node:timers/promises";
 import type { Binding, Conformance, DependencyBinding, PersistentAttachment, WorkspaceRevision } from "./types.js";
 import { validateWorkspaceRevision } from "./validation.js";
 
@@ -21,6 +22,89 @@ export const canonicalJson = (value: unknown): string => {
 };
 export const contentDigest = (value: unknown) =>
   `sha256:${createHash("sha256").update(canonicalJson(value)).digest("hex")}`;
+/** Same canonical bytes as contentDigest, without monopolizing a live host's
+ * event loop while verifying large immutable metadata. No validation is skipped.
+ * This is for asynchronous loading, not a different build/wire identity. */
+export async function contentDigestAsync(value: unknown): Promise<string> {
+  // An explicit stack visits each node once; recursive generator delegation
+  // otherwise forwards every token through every ancestor of a deep plan.
+  type Frame = { kind: "value" | "array" | "object"; value: unknown; index?: number; keys?: string[]; wrote?: boolean };
+  const hash = createHash("sha256"),
+    stack: Frame[] = [{ kind: "value", value }],
+    active = new WeakSet<object>();
+  let buffer = "",
+    sliceStarted = performance.now(),
+    steps = 0;
+  const append = (part: string) => {
+    buffer += part;
+    if (buffer.length >= 65536) {
+      hash.update(buffer);
+      buffer = "";
+    }
+  };
+  while (stack.length) {
+    const frame = stack[stack.length - 1]!;
+    if (frame.kind === "value") {
+      const value = frame.value;
+      if (value !== null && typeof value === "object") {
+        if (active.has(value)) throw new Error("Cannot hash cyclic JSON values");
+        active.add(value);
+        frame.index = 0;
+        if (Array.isArray(value)) {
+          frame.kind = "array";
+          append("[");
+        } else {
+          if (Object.getPrototypeOf(value) !== Object.prototype && Object.getPrototypeOf(value) !== null)
+            throw new Error("Expected a plain JSON object");
+          frame.kind = "object";
+          frame.keys = Object.keys(value).sort(compareText);
+          frame.wrote = false;
+          append("{");
+        }
+      } else {
+        append(canonicalJson(value));
+        stack.pop();
+      }
+    } else if (frame.kind === "array") {
+      const array = frame.value as unknown[];
+      if (frame.index === array.length) {
+        append("]");
+        active.delete(array);
+        stack.pop();
+      } else {
+        const index = frame.index!;
+        frame.index = index + 1;
+        if (index) append(",");
+        // Match canonicalJson's Array.map behavior for sparse arrays too.
+        if (index in array) stack.push({ kind: "value", value: array[index] });
+      }
+    } else {
+      const object = frame.value as Record<string, unknown>;
+      if (frame.index === frame.keys!.length) {
+        append("}");
+        active.delete(object);
+        stack.pop();
+      } else {
+        const index = frame.index!;
+        frame.index = index + 1;
+        const key = frame.keys![index]!,
+          entry = object[key];
+        if (entry !== undefined) {
+          if (frame.wrote) append(",");
+          frame.wrote = true;
+          append(JSON.stringify(key) + ":");
+          stack.push({ kind: "value", value: entry });
+        }
+      }
+    }
+    if (++steps % 512 === 0 && performance.now() - sliceStarted >= 8) {
+      await setImmediate();
+      sliceStarted = performance.now();
+    }
+  }
+  hash.update(buffer);
+  return `sha256:${hash.digest("hex")}`;
+}
 const semantic = (value: unknown): unknown => {
   if (Array.isArray(value)) return value.map(semantic);
   if (value && typeof value === "object")
diff --git a/src/execution-world/artifacts.ts b/src/execution-world/artifacts.ts
index 85f05f1..b53e2d0 100644
--- a/src/execution-world/artifacts.ts
+++ b/src/execution-world/artifacts.ts
@@ -1,6 +1,13 @@
+import {
+  executionPlanDigestAsync,
+  type ExecutionPlan,
+  type PlanPackage,
+  ExecutionPlanError,
+  hexDigest,
+  executionVersions,
+} from "./plan.js";
 import { createHash } from "node:crypto";
 import { canonicalJson } from "../capability-model/evolution.js";
-import { type ExecutionPlan, type PlanPackage, ExecutionPlanError, hexDigest, executionVersions } from "./plan.js";
 
 export interface ArtifactFile {
   path: string;
@@ -359,7 +366,7 @@ export async function checkExecutionWorld(
 ): Promise<CheckedWorld> {
   if (canonicalJson(plan.definition.versions) !== canonicalJson(executionVersions))
     fail("world", "Unsupported plan codec versions");
-  if (hexDigest(plan.definition) !== plan.digest) fail("plan", "Plan digest mismatch");
+  if ((await executionPlanDigestAsync(plan)) !== plan.digest) fail("plan", "Plan digest mismatch");
   const manifests = inputs.map(parsePackageArtifacts);
   unique(
     manifests.map((m) => m.packageRevisionId),
diff --git a/src/execution-world/candidate.ts b/src/execution-world/candidate.ts
index c7c8b05..924fd73 100644
--- a/src/execution-world/candidate.ts
+++ b/src/execution-world/candidate.ts
@@ -1,7 +1,7 @@
 import { graphExecutionRepresentation } from "./graph-execution.js";
 import { lstat } from "node:fs/promises";
 import { join } from "node:path";
-import { hexDigest, ExecutionPlanError, type ExecutionPlan } from "./plan.js";
+import { hexDigest, hexDigestAsync, sealExecutionPlan, ExecutionPlanError, type ExecutionPlan } from "./plan.js";
 import {
   loadExecutionInstallation,
   createClientContractCatalog,
@@ -50,7 +50,7 @@ export async function loadCheckedInstallationCandidate(
       const input = await readJson(root, "candidate.json", scope);
       try {
         const { executionContracts: _legacyContracts, ...workspace } = input.value;
-        return hexDigest(workspace);
+        return await hexDigestAsync(workspace);
       } finally {
         input.releaseTree();
       }
@@ -72,8 +72,8 @@ export async function loadCheckedInstallationCandidate(
     const [plan, artifacts, source, entryRequest, kernel, queries] = values;
     if (
       plan?.definition?.codec !== "camino-execution-plan-v1" ||
-      hexDigest(plan.definition) !== plan.digest ||
-      workspaceDigest !== hexDigest(plan.definition.workspace)
+      !(await sealExecutionPlan(plan)) ||
+      workspaceDigest !== (await hexDigestAsync(plan.definition.workspace))
     )
       throw new ExecutionPlanError(
         "CANDIDATE_PLAN_MISMATCH",
@@ -117,7 +117,11 @@ export async function loadCheckedInstallationCandidate(
       ["kernel", kernel, "camino-kernel-program-v1"],
       ["queries", queries, "camino-query-program-v1"],
     ] as const)
-      if (program?.codec !== codec || program.plan !== kernel.plan || hexDigest(program) !== artifacts.programs?.[name])
+      if (
+        program?.codec !== codec ||
+        program.plan !== kernel.plan ||
+        (await hexDigestAsync(program)) !== artifacts.programs?.[name]
+      )
         throw new ExecutionPlanError(
           "CANDIDATE_PROGRAM_MISMATCH",
           name,
@@ -126,16 +130,17 @@ export async function loadCheckedInstallationCandidate(
     const expectedGraph = graphExecutionRepresentation(plan, installation, kernel, queries);
     // The stored graph embeds the same kernel/query programs. Validate it in a
     // short-lived scope and retain the representation that shares those trees.
-    await (async () => {
+    const graphDigest = await (async () => {
       const input = await readJson(root, "graph-execution.json", scope);
       try {
-        const digest = hexDigest(input.value);
-        if (digest !== hexDigest(expectedGraph) || artifacts.execution !== digest)
+        const digest = await hexDigestAsync(input.value);
+        if (digest !== (await hexDigestAsync(expectedGraph)) || artifacts.execution !== digest)
           throw new ExecutionPlanError(
             "CANDIDATE_EXECUTION_MISMATCH",
             root,
             "Stored graph execution differs from checked inputs",
           );
+        return digest;
       } finally {
         input.releaseTree();
       }
@@ -164,7 +169,8 @@ export async function loadCheckedInstallationCandidate(
     return {
       reference,
       workspace: plan.definition.workspace.workspaceId,
-      world: hexDigest(expectedGraph),
+      // The checked representation was already compared with this digest.
+      world: graphDigest,
       plan: kernel.plan as string,
       graphExecution: expectedGraph,
       provenance,
diff --git a/src/execution-world/client-contracts.ts b/src/execution-world/client-contracts.ts
index 59f2e7b..11ebdd2 100644
--- a/src/execution-world/client-contracts.ts
+++ b/src/execution-world/client-contracts.ts
@@ -1,3 +1,4 @@
+import { executionPlanDigest, type ExecutionPlan, resolvePlannedOperation, ExecutionPlanError } from "./plan.js";
 import type {
   InterfaceRevision,
   InterfaceOperation,
@@ -6,7 +7,7 @@ import type {
 } from "../capability-model/types.js";
 import { canonicalJson } from "../capability-model/evolution.js";
 import { portableValueSchema, tsType } from "../bindings/portable.js";
-import { type ExecutionPlan, resolvePlannedOperation, hexDigest, ExecutionPlanError } from "./plan.js";
+
 import type { BindingSchema } from "../bindings/index.js";
 import type { PackageBuildContract } from "./build-contract.js";
 import { preparationArtifact, type ReactPreparationArtifact } from "../react-build/declarations.js";
@@ -55,7 +56,7 @@ export function publicOperationContract(
 }
 /** Resolve a public contract to internal dispatch. This does not authorize the receiver. */
 export function linkInterfaceOperation(plan: ExecutionPlan, atom: string, contract: PublicOperationContract) {
-  if (hexDigest(plan.definition) !== plan.digest)
+  if (executionPlanDigest(plan) !== plan.digest)
     throw new ExecutionPlanError("INVALID_PLAN", atom, "Invalid execution plan digest");
   const iface = plan.definition.workspace.interfaceImports.find((i) => i.revisionId === contract.interface);
   const operation = iface?.members.flatMap((m) => m.operations).find((o) => o.id === contract.operation);
@@ -97,7 +98,7 @@ export function publicQueryContract(pkg: PackageRevision, queryId: string): Publ
   };
 }
 export function linkPackageQuery(plan: ExecutionPlan, contract: PublicQueryContract) {
-  if (hexDigest(plan.definition) !== plan.digest)
+  if (executionPlanDigest(plan) !== plan.digest)
     throw new ExecutionPlanError("INVALID_PLAN", contract.query, "Invalid execution plan digest");
   const pkg = plan.definition.workspace.packageImports.find((p) => p.revisionId === contract.package);
   if (!pkg || canonicalJson(publicQueryContract(pkg, contract.query)) !== canonicalJson(contract))
diff --git a/src/execution-world/execution-groups.ts b/src/execution-world/execution-groups.ts
index 2b07126..116ade0 100644
--- a/src/execution-world/execution-groups.ts
+++ b/src/execution-world/execution-groups.ts
@@ -1,3 +1,4 @@
+import { executionPlanDigestAsync, type ExecutionPlan, hexDigest, hexDigestAsync, ExecutionPlanError } from "./plan.js";
 import { portableReflectionValue } from "./reflection.js";
 import type {
   BoundDependency,
@@ -6,7 +7,6 @@ import type {
   PersistentAttachment,
 } from "../capability-model/types.js";
 import { type ExecutionInstallation, type ExecutionGroupIdentity } from "./installation.js";
-import { type ExecutionPlan, hexDigest, ExecutionPlanError } from "./plan.js";
 
 export interface ExecutionEnvironment {
   /** Explicit host placement. Merely including an optional module does not select it. */
@@ -23,12 +23,12 @@ export interface InstalledExecutionGroup extends ExecutionGroupIdentity {
 }
 /** Conservative outbound closure. Runtime graph values, reverse callers, source
  * provenance and the workspace epoch are deliberately absent from this identity. */
-export function compileExecutionGroups(
+export async function compileExecutionGroups(
   plan: ExecutionPlan,
   installation: ExecutionInstallation,
   environments: Readonly<Record<string, ExecutionEnvironment>>,
-): InstalledExecutionGroup[] {
-  if (installation.plan !== plan.digest || hexDigest(plan.definition) !== plan.digest)
+): Promise<InstalledExecutionGroup[]> {
+  if (installation.plan !== plan.digest || (await executionPlanDigestAsync(plan)) !== plan.digest)
     throw new ExecutionPlanError("GROUP_PLAN_MISMATCH", plan.digest, "Expected one checked installation");
   const workspace = plan.definition.workspace;
   const packages = new Map(workspace.packageImports.map((p) => [p.revisionId as string, p]));
@@ -82,178 +82,175 @@ export function compileExecutionGroups(
   };
   const bindingContract = (value: DependencyBinding) =>
     value.kind === "query" ? { ...value, packageRevisionId: logical(value.packageRevisionId) } : value;
-  return installation.packages
-    .filter((p) => !!implementations.get(p.revision))
-    .map((root) => {
-      const consumed = new Map<string, unknown>(),
-        visited = new Set<string>(),
-        visitedQueries = new Set<string>(),
-        consumedPackages = new Set<string>();
-      const remember = (key: string, value: unknown) => consumed.set(key, value);
-      const storage = (id: string) => {
-        const value = attachments.get(id);
-        if (!value) throw new ExecutionPlanError("GROUP_STORAGE_MISSING", id, "Uninstalled consumed storage");
-        remember(`storage:${id}`, attachmentContract(value));
-      };
-      // Deletion may visit related objects and their owned state. Conservatively
-      // include the connected schema component, including possible future edges.
-      const lifecycle = (atom: string) => {
-        const visited = new Set<string>(),
-          pending = [atom];
-        const atoms = (
-          constraint: Extract<PersistentAttachment, { kind: "edge" }>["endpoints"][number]["constraint"],
-        ) =>
-          constraint.kind === "atom"
-            ? [constraint.atomId as string]
-            : workspace.conformances
-                .filter((c) => c.interfaceRevisionId === constraint.interfaceRevisionId)
-                .map((c) => c.atomId as string);
-        while (pending.length) {
-          const current = pending.pop()!;
-          if (visited.has(current)) continue;
-          visited.add(current);
-          for (const owner of workspace.conformances.filter((c) => c.atomId === current))
-            for (const attachment of owner.privateAttachments) storage(attachment.id);
-          for (const attachment of attachments.values())
-            if (attachment.kind === "edge" && attachment.endpoints.some((e) => atoms(e.constraint).includes(current))) {
-              storage(attachment.id);
-              pending.push(...attachment.endpoints.flatMap((e) => atoms(e.constraint)));
-            }
-        }
-      };
-      const targets = (binding: DependencyBinding, atom: string): string[] => {
-        if (binding.kind === "interface" && binding.receiver === "input")
-          return workspace.conformances
-            .filter((c) => c.interfaceRevisionId === binding.interfaceRevisionId)
-            .map((c) => c.atomId);
-        if (!("via" in binding) || !binding.via) return [atom];
-        storage(binding.via.edgeTypeId);
-        const edge = attachments.get(binding.via.edgeTypeId);
-        if (!edge || edge.kind !== "edge")
-          throw new ExecutionPlanError("GROUP_EDGE_MISSING", atom, "Missing traversal edge");
-        const endpoint = edge.endpoints.find((e) => e.projectionId !== binding.via!.projectionId)!;
-        const constraint = endpoint.constraint;
-        return constraint.kind === "atom"
-          ? [constraint.atomId]
+  const groups: InstalledExecutionGroup[] = [];
+  for (const root of installation.packages.filter((p) => !!implementations.get(p.revision))) {
+    const consumed = new Map<string, unknown>(),
+      visited = new Set<string>(),
+      visitedQueries = new Set<string>(),
+      consumedPackages = new Set<string>();
+    const remember = (key: string, value: unknown) => consumed.set(key, value);
+    const storage = (id: string) => {
+      const value = attachments.get(id);
+      if (!value) throw new ExecutionPlanError("GROUP_STORAGE_MISSING", id, "Uninstalled consumed storage");
+      remember(`storage:${id}`, attachmentContract(value));
+    };
+    // Deletion may visit related objects and their owned state. Conservatively
+    // include the connected schema component, including possible future edges.
+    const lifecycle = (atom: string) => {
+      const visited = new Set<string>(),
+        pending = [atom];
+      const atoms = (constraint: Extract<PersistentAttachment, { kind: "edge" }>["endpoints"][number]["constraint"]) =>
+        constraint.kind === "atom"
+          ? [constraint.atomId as string]
           : workspace.conformances
               .filter((c) => c.interfaceRevisionId === constraint.interfaceRevisionId)
-              .map((c) => c.atomId);
-      };
-      const query = (revision: string, id: string) => {
-        const key = JSON.stringify([revision, id]);
-        if (visitedQueries.has(key)) return;
-        visitedQueries.add(key);
-        const value = plan.definition.queries.find((q) => q.id === key);
-        if (!value) throw new ExecutionPlanError("GROUP_QUERY_MISSING", key, "Missing consumed query");
-        remember(`query:${JSON.stringify([logical(revision), id])}`, value.query.checked.definitionDigest);
-        for (const operation of value.operations) visit(operation);
-      };
-      const dependencies = (entry: PackageExport, bindings: readonly BoundDependency[], atom: string) => {
-        for (const bound of bindings) {
-          const target = bound.binding,
-            port = entry.dependencyPorts.find((p) => p.id === bound.portId)!;
-          if ("via" in target && target.via) storage(target.via.edgeTypeId);
-          if (target.kind === "reflection") {
-            for (const selector of target.selectors)
-              remember("reflection:" + selector, portableReflectionValue(workspace, selector));
-          } else if (target.kind === "state") storage(target.slotId);
-          else if (target.kind === "edge") storage(target.edgeTypeId);
-          else if (target.kind === "query") query(target.packageRevisionId, target.queryId);
-          else if (target.kind === "interface" && port.requirement.kind === "interface") {
-            const iface = workspace.interfaceImports.find((i) => i.revisionId === target.interfaceRevisionId)!;
-            for (const targetAtom of targets(target, atom))
-              for (const op of port.requirement.operations ??
-                iface.members.flatMap((m) => m.operations.map((o) => o.id)))
-                visit(JSON.stringify([targetAtom, target.interfaceRevisionId, op]));
-          } else if (target.kind === "creation") {
-            for (const seed of target.owners) {
-              const owner = workspace.conformances.find(
-                (c) => c.atomId === target.atomId && c.interfaceRevisionId === seed.interfaceRevisionId,
-              )!;
-              remember(`birth:${owner.id}`, {
-                id: owner.id,
-                atom: owner.atomId,
-                interface: owner.interfaceRevisionId,
-                initialization: owner.initialization ?? [],
-              });
-              for (const attachment of owner.privateAttachments) storage(attachment.id);
-            }
-          } else
-            throw new ExecutionPlanError(
-              "GROUP_DEPENDENCY_UNSUPPORTED",
-              bound.portId,
-              "Cannot establish execution reuse for this dependency",
-            );
-        }
-      };
-      const visit = (key: string) => {
-        if (visited.has(key)) return;
-        visited.add(key);
-        const operation = operations.get(key);
-        if (!operation) throw new ExecutionPlanError("GROUP_OPERATION_MISSING", key, "Missing consumed operation");
-        const binding = operation.binding;
-        if (binding.kind === "package") {
-          const pkg = packages.get(binding.packageRevisionId)!;
-          const implementation = implementations.get(pkg.revisionId);
-          if (!implementation)
-            throw new ExecutionPlanError(
-              "GROUP_IMPLEMENTATION_MISSING",
-              pkg.revisionId,
-              "Consumed package has no selected server implementation",
-            );
-          consumedPackages.add(pkg.packageId);
-          remember(`implementation:${pkg.packageId}`, {
-            digest: implementation.contentDigest,
-            environment: environment(pkg.revisionId),
-          });
-          const entry = pkg.exports.find((e) => e.id === binding.exportId)!;
-          const bindings = binding.dependencies.map((d) => ({ portId: d.portId, binding: bindingContract(d.binding) }));
-          const acceptance = (binding.acceptanceDependencies ?? []).map((d) => ({
-            portId: d.portId,
-            binding: bindingContract(d.binding),
-          }));
-          const contract = {
-            input: operation.input,
-            output: operation.output,
-            execution: operation.execution,
-            scope: operation.scope,
-            binding: {
-              package: pkg.packageId,
-              export: binding.exportId,
-              dependencies: bindings,
-              acceptanceDependencies: acceptance,
-            },
-          };
-          // Deduplicate aliases of the same bound export, rather than keying its owner by reverse callers.
-          remember(`binding:${hexDigest(contract)}`, contract);
-          dependencies(entry, binding.dependencies, operation.atomId);
-          if (entry.acceptanceExportId)
-            dependencies(
-              pkg.exports.find((e) => e.id === entry.acceptanceExportId)!,
-              binding.acceptanceDependencies ?? [],
-              operation.atomId,
-            );
-        } else {
-          remember(`operation:${key}`, operation);
-          if (binding.kind === "state") storage(binding.slotId);
-          if (binding.kind === "edge") storage(binding.edgeTypeId);
-          if (binding.kind === "lifecycle") lifecycle(operation.atomId);
-        }
-      };
-      for (const operation of plan.definition.operations)
-        if (operation.binding.kind === "package" && operation.binding.packageRevisionId === root.revision)
-          visit(operation.key);
-      const own = implementations.get(root.revision)!;
-      const exports = packages.get(root.revision)!.exports.map(({ displayName: _name, dependencyPorts, ...entry }) => ({
-        ...entry,
-        dependencyPorts: dependencyPorts.map(({ displayName: _name, ...port }) => port),
-      }));
-      const entries = [...consumed].sort(([a], [b]) => (a < b ? -1 : a > b ? 1 : 0));
-      return {
-        logicalId: logical(root.revision),
-        packageRevision: root.revision,
-        executionDigest: `sha256:${hexDigest({ implementation: own.contentDigest, exports, environment: environment(root.revision), versions: plan.definition.versions, consumed: entries })}`,
-        consumedPackages: [...consumedPackages].sort(),
-      };
+              .map((c) => c.atomId as string);
+      while (pending.length) {
+        const current = pending.pop()!;
+        if (visited.has(current)) continue;
+        visited.add(current);
+        for (const owner of workspace.conformances.filter((c) => c.atomId === current))
+          for (const attachment of owner.privateAttachments) storage(attachment.id);
+        for (const attachment of attachments.values())
+          if (attachment.kind === "edge" && attachment.endpoints.some((e) => atoms(e.constraint).includes(current))) {
+            storage(attachment.id);
+            pending.push(...attachment.endpoints.flatMap((e) => atoms(e.constraint)));
+          }
+      }
+    };
+    const targets = (binding: DependencyBinding, atom: string): string[] => {
+      if (binding.kind === "interface" && binding.receiver === "input")
+        return workspace.conformances
+          .filter((c) => c.interfaceRevisionId === binding.interfaceRevisionId)
+          .map((c) => c.atomId);
+      if (!("via" in binding) || !binding.via) return [atom];
+      storage(binding.via.edgeTypeId);
+      const edge = attachments.get(binding.via.edgeTypeId);
+      if (!edge || edge.kind !== "edge")
+        throw new ExecutionPlanError("GROUP_EDGE_MISSING", atom, "Missing traversal edge");
+      const endpoint = edge.endpoints.find((e) => e.projectionId !== binding.via!.projectionId)!;
+      const constraint = endpoint.constraint;
+      return constraint.kind === "atom"
+        ? [constraint.atomId]
+        : workspace.conformances
+            .filter((c) => c.interfaceRevisionId === constraint.interfaceRevisionId)
+            .map((c) => c.atomId);
+    };
+    const query = (revision: string, id: string) => {
+      const key = JSON.stringify([revision, id]);
+      if (visitedQueries.has(key)) return;
+      visitedQueries.add(key);
+      const value = plan.definition.queries.find((q) => q.id === key);
+      if (!value) throw new ExecutionPlanError("GROUP_QUERY_MISSING", key, "Missing consumed query");
+      remember(`query:${JSON.stringify([logical(revision), id])}`, value.query.checked.definitionDigest);
+      for (const operation of value.operations) visit(operation);
+    };
+    const dependencies = (entry: PackageExport, bindings: readonly BoundDependency[], atom: string) => {
+      for (const bound of bindings) {
+        const target = bound.binding,
+          port = entry.dependencyPorts.find((p) => p.id === bound.portId)!;
+        if ("via" in target && target.via) storage(target.via.edgeTypeId);
+        if (target.kind === "reflection") {
+          for (const selector of target.selectors)
+            remember("reflection:" + selector, portableReflectionValue(workspace, selector));
+        } else if (target.kind === "state") storage(target.slotId);
+        else if (target.kind === "edge") storage(target.edgeTypeId);
+        else if (target.kind === "query") query(target.packageRevisionId, target.queryId);
+        else if (target.kind === "interface" && port.requirement.kind === "interface") {
+          const iface = workspace.interfaceImports.find((i) => i.revisionId === target.interfaceRevisionId)!;
+          for (const targetAtom of targets(target, atom))
+            for (const op of port.requirement.operations ?? iface.members.flatMap((m) => m.operations.map((o) => o.id)))
+              visit(JSON.stringify([targetAtom, target.interfaceRevisionId, op]));
+        } else if (target.kind === "creation") {
+          for (const seed of target.owners) {
+            const owner = workspace.conformances.find(
+              (c) => c.atomId === target.atomId && c.interfaceRevisionId === seed.interfaceRevisionId,
+            )!;
+            remember(`birth:${owner.id}`, {
+              id: owner.id,
+              atom: owner.atomId,
+              interface: owner.interfaceRevisionId,
+              initialization: owner.initialization ?? [],
+            });
+            for (const attachment of owner.privateAttachments) storage(attachment.id);
+          }
+        } else
+          throw new ExecutionPlanError(
+            "GROUP_DEPENDENCY_UNSUPPORTED",
+            bound.portId,
+            "Cannot establish execution reuse for this dependency",
+          );
+      }
+    };
+    const visit = (key: string) => {
+      if (visited.has(key)) return;
+      visited.add(key);
+      const operation = operations.get(key);
+      if (!operation) throw new ExecutionPlanError("GROUP_OPERATION_MISSING", key, "Missing consumed operation");
+      const binding = operation.binding;
+      if (binding.kind === "package") {
+        const pkg = packages.get(binding.packageRevisionId)!;
+        const implementation = implementations.get(pkg.revisionId);
+        if (!implementation)
+          throw new ExecutionPlanError(
+            "GROUP_IMPLEMENTATION_MISSING",
+            pkg.revisionId,
+            "Consumed package has no selected server implementation",
+          );
+        consumedPackages.add(pkg.packageId);
+        remember(`implementation:${pkg.packageId}`, {
+          digest: implementation.contentDigest,
+          environment: environment(pkg.revisionId),
+        });
+        const entry = pkg.exports.find((e) => e.id === binding.exportId)!;
+        const bindings = binding.dependencies.map((d) => ({ portId: d.portId, binding: bindingContract(d.binding) }));
+        const acceptance = (binding.acceptanceDependencies ?? []).map((d) => ({
+          portId: d.portId,
+          binding: bindingContract(d.binding),
+        }));
+        const contract = {
+          input: operation.input,
+          output: operation.output,
+          execution: operation.execution,
+          scope: operation.scope,
+          binding: {
+            package: pkg.packageId,
+            export: binding.exportId,
+            dependencies: bindings,
+            acceptanceDependencies: acceptance,
+          },
+        };
+        // Deduplicate aliases of the same bound export, rather than keying its owner by reverse callers.
+        remember(`binding:${hexDigest(contract)}`, contract);
+        dependencies(entry, binding.dependencies, operation.atomId);
+        if (entry.acceptanceExportId)
+          dependencies(
+            pkg.exports.find((e) => e.id === entry.acceptanceExportId)!,
+            binding.acceptanceDependencies ?? [],
+            operation.atomId,
+          );
+      } else {
+        remember(`operation:${key}`, operation);
+        if (binding.kind === "state") storage(binding.slotId);
+        if (binding.kind === "edge") storage(binding.edgeTypeId);
+        if (binding.kind === "lifecycle") lifecycle(operation.atomId);
+      }
+    };
+    for (const operation of plan.definition.operations)
+      if (operation.binding.kind === "package" && operation.binding.packageRevisionId === root.revision)
+        visit(operation.key);
+    const own = implementations.get(root.revision)!;
+    const exports = packages.get(root.revision)!.exports.map(({ displayName: _name, dependencyPorts, ...entry }) => ({
+      ...entry,
+      dependencyPorts: dependencyPorts.map(({ displayName: _name, ...port }) => port),
+    }));
+    const entries = [...consumed].sort(([a], [b]) => (a < b ? -1 : a > b ? 1 : 0));
+    groups.push({
+      logicalId: logical(root.revision),
+      packageRevision: root.revision,
+      executionDigest: `sha256:${await hexDigestAsync({ implementation: own.contentDigest, exports, environment: environment(root.revision), versions: plan.definition.versions, consumed: entries })}`,
+      consumedPackages: [...consumedPackages].sort(),
     });
+  }
+  return groups;
 }
diff --git a/src/execution-world/graph-execution.ts b/src/execution-world/graph-execution.ts
index 93fb031..ab2b009 100644
--- a/src/execution-world/graph-execution.ts
+++ b/src/execution-world/graph-execution.ts
@@ -1,4 +1,5 @@
-import { ExecutionPlanError, hexDigest, type ExecutionPlan } from "./plan.js";
+import { executionPlanDigest, ExecutionPlanError, hexDigest, type ExecutionPlan } from "./plan.js";
+
 import type { ExecutionInstallation } from "./installation.js";
 
 /** Execution inputs, not build evidence. Nominal revision IDs remain dispatch
@@ -10,7 +11,7 @@ export function graphExecutionRepresentation(
   kernel: unknown,
   queries: unknown,
 ) {
-  if (installation.plan !== plan.digest || hexDigest(plan.definition) !== plan.digest)
+  if (installation.plan !== plan.digest || executionPlanDigest(plan) !== plan.digest)
     throw new ExecutionPlanError("GRAPH_PLAN_MISMATCH", "graph", "Expected one checked installation");
   if (
     !kernel ||
diff --git a/src/execution-world/installation.ts b/src/execution-world/installation.ts
index 0cb526a..92d9d22 100644
--- a/src/execution-world/installation.ts
+++ b/src/execution-world/installation.ts
@@ -1,9 +1,10 @@
+import { executionPlanDigestAsync, ExecutionPlanError, type ExecutionPlan } from "./plan.js";
 import { compileInspectionTemplates, type InspectionTemplate, type InspectionKernel } from "./inspection.js";
 import path from "node:path";
 import { loadCheckedArtifactWorld } from "./receipts.js";
 import { contentArtifactUrl, loadArtifactWorld, type LoadedArtifactWorld } from "./files.js";
 import { selectArtifactImplementation, type ArtifactImplementation, type ComponentArtifact } from "./artifacts.js";
-import { ExecutionPlanError, hexDigest, type ExecutionPlan } from "./plan.js";
+
 import {
   publicOperationContract,
   publicQueryContract,
@@ -41,13 +42,13 @@ export interface ClientContractCatalog {
   }[];
 }
 /** Explicit projection prevents accidental spreading of filesystem roots or private bindings. */
-export function clientContractCatalog(
+export async function clientContractCatalog(
   plan: ExecutionPlan,
   installation: ExecutionInstallation,
   requestedPackages: readonly string[],
   checkedKernel?: InspectionKernel,
-): ClientContractCatalog {
-  if (installation.plan !== plan.digest || hexDigest(plan.definition) !== plan.digest)
+): Promise<ClientContractCatalog> {
+  if (installation.plan !== plan.digest || (await executionPlanDigestAsync(plan)) !== plan.digest)
     throw new ExecutionPlanError(
       "CATALOG_PLAN_MISMATCH",
       plan.digest,
@@ -112,6 +113,7 @@ export function createClientContractCatalog(
   const revisions = plan.definition.workspace.packageImports.map((pkg) => pkg.revisionId);
   const installed = new Set<string>(revisions);
   let catalog: ClientContractCatalog | undefined;
+  let preparing: Promise<void> | undefined;
   let release: (() => void) | undefined;
   let closed = false;
   const freeze = (value: unknown, seen = new WeakSet<object>()) => {
@@ -121,7 +123,7 @@ export function createClientContractCatalog(
     Object.freeze(value);
   };
   return {
-    select(requestedPackages: readonly string[]): ClientContractCatalog {
+    async select(requestedPackages: readonly string[]): Promise<ClientContractCatalog> {
       if (closed) throw Error("CANDIDATE_METADATA_CLOSED");
       for (const revision of requestedPackages)
         if (!installed.has(revision))
@@ -129,22 +131,29 @@ export function createClientContractCatalog(
       if (!catalog) {
         // Like other candidate admission charges, this is an allocation estimate,
         // not a V8 heap limit. The process/cgroup ceiling bounds transient work.
-        const reservation = metadata.reserve(32 * 1024 * 1024);
-        try {
-          const compiled = clientContractCatalog(plan, installation, revisions, checkedKernel);
-          const bytes = Buffer.byteLength(JSON.stringify(compiled));
-          if (bytes > 8 * 1024 * 1024) throw Error("CANDIDATE_CATALOG_LIMIT");
-          freeze(compiled);
-          // No await between reservations: replacing the transient upper bound
-          // with a smaller retained estimate cannot race another admission.
-          reservation();
-          release = metadata.reserve(Math.max(64 * 1024, bytes * 4));
-          catalog = compiled;
-        } catch (error) {
-          reservation();
-          throw error;
-        }
+        preparing ??= (async () => {
+          const reservation = metadata.reserve(32 * 1024 * 1024);
+          try {
+            const compiled = await clientContractCatalog(plan, installation, revisions, checkedKernel);
+            if (closed) throw Error("CANDIDATE_METADATA_CLOSED");
+            const bytes = Buffer.byteLength(JSON.stringify(compiled));
+            if (bytes > 8 * 1024 * 1024) throw Error("CANDIDATE_CATALOG_LIMIT");
+            freeze(compiled);
+            // No await between reservations: replacing the transient upper bound
+            // with a smaller retained estimate cannot race another admission.
+            reservation();
+            release = metadata.reserve(Math.max(64 * 1024, bytes * 4));
+            catalog = compiled;
+          } catch (error) {
+            reservation();
+            throw error;
+          }
+        })().finally(() => {
+          preparing = undefined;
+        });
+        await preparing;
       }
+      if (closed || !catalog) throw Error("CANDIDATE_METADATA_CLOSED");
       const requested = new Set(requestedPackages);
       return {
         inspections: catalog.inspections,
diff --git a/src/execution-world/kernel.ts b/src/execution-world/kernel.ts
index 47d9ff5..4a23a0c 100644
--- a/src/execution-world/kernel.ts
+++ b/src/execution-world/kernel.ts
@@ -1,3 +1,4 @@
+import { executionPlanDigest, type ExecutionPlan, ExecutionPlanError, hexDigest } from "./plan.js";
 import { portableReflectionType, portableReflectionValue } from "./reflection.js";
 import type {
   ValueType,
@@ -7,7 +8,7 @@ import type {
   BoundDependency,
   PackageExport,
 } from "../capability-model/types.js";
-import { type ExecutionPlan, ExecutionPlanError, hexDigest } from "./plan.js";
+
 import { portableValueSchema } from "../bindings/portable.js";
 import { subscriptionContract } from "../capability-model/journals.js";
 type PreparedStep = string | null | { case: string; id: string };
@@ -25,7 +26,7 @@ function preparedInputPaths(type: ValueType, path: PreparedStep[] = []): Prepare
 }
 /** Small data-only interpreter input; no compiler, parser, Node module or SQL dependency reaches the browser. */
 export function compileKernelProgram(plan: ExecutionPlan): unknown {
-  if (hexDigest(plan.definition) !== plan.digest)
+  if (executionPlanDigest(plan) !== plan.digest)
     throw new ExecutionPlanError("INVALID_PLAN", "kernel", "Plan digest mismatch");
   const workspace = plan.definition.workspace;
   if (workspace.sharedAttachments.some((attachment) => attachment.kind !== "edge"))
diff --git a/src/execution-world/metadata.ts b/src/execution-world/metadata.ts
index 01cf497..a06e35c 100644
--- a/src/execution-world/metadata.ts
+++ b/src/execution-world/metadata.ts
@@ -22,6 +22,9 @@ export class CandidateMetadataBudget {
   snapshot() {
     return { bytes: this.bytes, candidates: this.scopes, owners: this.owners.size, limits: this.limits };
   }
+  ownedBytes(owner: string) {
+    return this.owners.get(owner) ?? 0;
+  }
   acquire(owner: string) {
     if (!owner || owner.length > 4096) throw Error("INVALID_CANDIDATE_METADATA_OWNER");
     if (this.scopes >= this.limits.candidates) throw Error("CANDIDATE_METADATA_LIMIT");
diff --git a/src/execution-world/placement.ts b/src/execution-world/placement.ts
index 569b96a..e00e77f 100644
--- a/src/execution-world/placement.ts
+++ b/src/execution-world/placement.ts
@@ -1,6 +1,7 @@
+import { executionPlanDigest, ExecutionPlanError, hexDigest, type ExecutionPlan } from "./plan.js";
 import { parse } from "@babel/parser";
 import { builtinModules } from "node:module";
-import { ExecutionPlanError, hexDigest, type ExecutionPlan } from "./plan.js";
+
 import type { ExecutionInstallation } from "./installation.js";
 import type { ArtifactImplementation, ArtifactReader } from "./artifacts.js";
 
@@ -212,7 +213,7 @@ export async function reportExecutionPlacement(
   installation: ExecutionInstallation,
   read: ArtifactReader,
 ) {
-  if (installation.plan !== plan.digest || hexDigest(plan.definition) !== plan.digest)
+  if (installation.plan !== plan.digest || executionPlanDigest(plan) !== plan.digest)
     throw new ExecutionPlanError(
       "PLACEMENT_PLAN_MISMATCH",
       plan.digest,
diff --git a/src/execution-world/plan.ts b/src/execution-world/plan.ts
index da65c4c..e941965 100644
--- a/src/execution-world/plan.ts
+++ b/src/execution-world/plan.ts
@@ -11,12 +11,13 @@ import type {
   OperationId,
 } from "../capability-model/types.js";
 import { validateWorkspaceRevision } from "../capability-model/validation.js";
-import { canonicalJson, contentDigest } from "../capability-model/evolution.js";
+import { canonicalJson, contentDigest, contentDigestAsync } from "../capability-model/evolution.js";
 import { resolveForwardedBinding } from "../capability-model/forwarding.js";
 import { linkQueries, type LinkedQuery } from "../query/link.js";
 import { type BindingSchema } from "../bindings/index.js";
 import { unsupportedQueryOperator } from "./query-operators.js";
 import { packageBuildContexts } from "./build-contract.js";
+import { setImmediate } from "node:timers/promises";
 
 export class ExecutionPlanError extends Error {
   constructor(
@@ -29,6 +30,56 @@ export class ExecutionPlanError extends Error {
   }
 }
 export const hexDigest = (value: unknown): string => contentDigest(value).slice("sha256:".length);
+export const hexDigestAsync = async (value: unknown): Promise<string> =>
+  (await contentDigestAsync(value)).slice("sha256:".length);
+// Checked runtime metadata is owned JSON, not live Graph data. Reuse its proof
+// only after every reachable record is immutable. Weak keys retain neither old
+// Candidates nor an application cache; unsealed compiler inputs are rehashed.
+const sealedPlanDigests = new WeakMap<ExecutionPlan, string>();
+export const executionPlanDigest = (plan: ExecutionPlan): string =>
+  sealedPlanDigests.get(plan) ?? hexDigest(plan.definition);
+export const executionPlanDigestAsync = async (plan: ExecutionPlan): Promise<string> =>
+  sealedPlanDigests.get(plan) ?? (await hexDigestAsync(plan.definition));
+/** Transfers owned parsed JSON into immutable runtime metadata. Freeze before
+ * yielding to hashing so concurrent mutation cannot invalidate the proof. */
+export async function sealExecutionPlan(plan: ExecutionPlan): Promise<boolean> {
+  if (sealedPlanDigests.has(plan)) return true;
+  if (!Object.hasOwn(plan, "definition") || !Object.hasOwn(plan, "digest")) return false;
+  const pending: object[] = [plan],
+    seen = new WeakSet<object>();
+  let sliceStarted = performance.now(),
+    count = 0;
+  while (pending.length) {
+    const value = pending.pop()!;
+    if (seen.has(value)) continue;
+    if (
+      !Array.isArray(value) &&
+      Object.getPrototypeOf(value) !== Object.prototype &&
+      Object.getPrototypeOf(value) !== null
+    )
+      throw new ExecutionPlanError("INVALID_PLAN_JSON", "plan", "Expected owned JSON records");
+    for (const key of Reflect.ownKeys(value)) {
+      const descriptor = Object.getOwnPropertyDescriptor(value, key)!;
+      if (typeof key !== "string" || !Object.hasOwn(descriptor, "value"))
+        throw new ExecutionPlanError(
+          "INVALID_PLAN_JSON",
+          "plan",
+          "Runtime metadata cannot contain accessors or symbols",
+        );
+      if (descriptor.value !== null && typeof descriptor.value === "object") pending.push(descriptor.value);
+    }
+    Object.freeze(value);
+    seen.add(value);
+    if (++count % 1024 === 0 && performance.now() - sliceStarted >= 8) {
+      await setImmediate();
+      sliceStarted = performance.now();
+    }
+  }
+  const digest = await hexDigestAsync(plan.definition);
+  if (digest !== plan.digest) return false;
+  sealedPlanDigests.set(plan, digest);
+  return true;
+}
 const sorted = <T>(values: readonly T[], key: (value: T) => string): T[] =>
   [...values].sort((a, b) => (key(a) < key(b) ? -1 : key(a) > key(b) ? 1 : 0));
 export const publicOperationKey = (atom: string, iface: string, operation: string): string =>
diff --git a/src/execution-world/projections.ts b/src/execution-world/projections.ts
index 2eb24af..d00913a 100644
--- a/src/execution-world/projections.ts
+++ b/src/execution-world/projections.ts
@@ -1,4 +1,5 @@
-import { ExecutionPlanError, hexDigest, type ExecutionPlan, type PlannedQuery } from "./plan.js";
+import { executionPlanDigest, ExecutionPlanError, type ExecutionPlan, type PlannedQuery } from "./plan.js";
+
 /** Contracts promised by a direct result. Interface dependencies are explicit; accidental
  * overlap among today's implementations does not silently widen an exported interface contract. */
 export function resultInterfaces(plan: ExecutionPlan, operationKey: string): string[] {
@@ -23,7 +24,7 @@ export function resultInterfaces(plan: ExecutionPlan, operationKey: string): str
 }
 /** Compile-time observeResult compatibility. Observation does not grant read or mutation authority. */
 export function checkResultProjection(plan: ExecutionPlan, operationKey: string, queryId: string): PlannedQuery {
-  if (hexDigest(plan.definition) !== plan.digest)
+  if (executionPlanDigest(plan) !== plan.digest)
     throw new ExecutionPlanError("INVALID_PLAN", "projection", "Plan digest mismatch");
   const query = plan.definition.queries.find((q) => q.id === queryId);
   if (!query) throw new ExecutionPlanError("UNKNOWN_PROJECTION", queryId, "No installed query");
diff --git a/src/execution-world/public-reflection.ts b/src/execution-world/public-reflection.ts
index d828670..68f08a1 100644
--- a/src/execution-world/public-reflection.ts
+++ b/src/execution-world/public-reflection.ts
@@ -1,27 +1,17 @@
-import { compileInspectionTemplates } from "./inspection.js";
-import { compileKernelProgram } from "./kernel.js";
-import { hexDigest, type ExecutionPlan } from "./plan.js";
-import { clientContractCatalog, type ExecutionInstallation } from "./installation.js";
+import { compileInspectionTemplates, type InspectionKernel } from "./inspection.js";
+import { hexDigestAsync, type ExecutionPlan } from "./plan.js";
+import type { ClientContractCatalog } from "./installation.js";
 import { publicOperationContract, publicQueryContract } from "./client-contracts.js";
 
-/** Explicit public projection. Never serialize conformance storage or package ports. */
-export function publicDefinitionSnapshot(plan: ExecutionPlan, installation: ExecutionInstallation) {
+/** Explicit public projection of checked inputs. Never serialize conformance
+ * storage or package ports, or recompile a historical Candidate at runtime.
+ * The caller supplies that Candidate's checked, cached public catalog. */
+export async function publicDefinitionSnapshot(
+  plan: ExecutionPlan,
+  kernel: InspectionKernel,
+  catalog: ClientContractCatalog,
+) {
   const workspace = plan.definition.workspace;
-  const kernel = compileKernelProgram(plan) as {
-    operations: {
-      atom: string;
-      interface: string;
-      operation: string;
-      unsupported: string | null;
-      effect: string;
-      targets: string[];
-    }[];
-  };
-  const catalog = clientContractCatalog(
-    plan,
-    installation,
-    installation.packages.map((pkg) => pkg.revision),
-  );
   const rows = {
     atoms: workspace.atoms.map((atom) => ({ id: atom.id, name: atom.displayName, documentation: atom.documentation })),
     interfaces: workspace.interfaceImports.map((iface) => ({
@@ -68,7 +58,7 @@ export function publicDefinitionSnapshot(plan: ExecutionPlan, installation: Exec
       ),
     })),
     queries: [
-      ...compileInspectionTemplates(plan).contracts.map((descriptor) => ({
+      ...compileInspectionTemplates(plan, kernel).contracts.map((descriptor) => ({
         id: JSON.stringify([descriptor.package, descriptor.query]),
         name: "Public inspection",
         package: descriptor.package,
@@ -100,5 +90,5 @@ export function publicDefinitionSnapshot(plan: ExecutionPlan, installation: Exec
     { id: string; [key: string]: unknown }[]
   >;
   for (const entries of Object.values(publicRows)) entries.sort((a, b) => (a.id < b.id ? -1 : a.id > b.id ? 1 : 0));
-  return { codec: "camino-definitions-v1" as const, id: hexDigest(publicRows), rows: publicRows };
+  return { codec: "camino-definitions-v1" as const, id: await hexDigestAsync(publicRows), rows: publicRows };
 }
diff --git a/src/execution-world/queries.ts b/src/execution-world/queries.ts
index 1513014..a924cdc 100644
--- a/src/execution-world/queries.ts
+++ b/src/execution-world/queries.ts
@@ -1,7 +1,8 @@
+import { executionPlanDigest, ExecutionPlanError, type ExecutionPlan } from "./plan.js";
 import { compileKernelProgram } from "./kernel.js";
 import { compileInspectionTemplates } from "./inspection.js";
 import { portableValueSchema } from "../bindings/portable.js";
-import { ExecutionPlanError, hexDigest, type ExecutionPlan } from "./plan.js";
+
 import type { ValueType } from "../capability-model/types.js";
 import { compileQueryComposition } from "../query/composition.js";
 import { queryTreeBlueprint } from "./query-trees.js";
@@ -24,7 +25,7 @@ const lowerTypes = (value: unknown): unknown =>
 /** Checked query IR and installed getter identities, without GraphQL schemas/parsers or SQL adapters.
  * Keep authored selection names only for output paths; field access uses resolved interface/member IDs. */
 export function compileQueryProgram(plan: ExecutionPlan): unknown {
-  if (hexDigest(plan.definition) !== plan.digest)
+  if (executionPlanDigest(plan) !== plan.digest)
     throw new ExecutionPlanError("INVALID_PLAN", "queries", "Plan digest mismatch");
   const allQueries = new Map(plan.definition.queries.map(({ id, query }) => [id, query.checked]));
   const compositions = plan.definition.workspace.packageImports.flatMap((pkg) =>
diff --git a/src/execution-world/query-document.ts b/src/execution-world/query-document.ts
index a897ab8..570a465 100644
--- a/src/execution-world/query-document.ts
+++ b/src/execution-world/query-document.ts
@@ -1,8 +1,9 @@
+import { executionPlanDigest, hexDigest, type ExecutionPlan, type PlannedQuery } from "./plan.js";
 import { compileQuery } from "../query/compile.js";
 import { linkQueries } from "../query/link.js";
 import { capabilityId } from "../capability-model/types.js";
 import { portableValueSchema } from "../bindings/portable.js";
-import { hexDigest, type ExecutionPlan, type PlannedQuery } from "./plan.js";
+
 import { compileKernelProgram } from "./kernel.js";
 import { queryProgramEntry } from "./queries.js";
 import { unsupportedQueryOperator } from "./query-operators.js";
@@ -17,7 +18,7 @@ export interface QueryDocument {
 /** Runtime query documents use the same language, nominal contracts, linking
  * and interpreter as packaged queries. They introduce no resources or code. */
 export async function compilePublicQuery(plan: ExecutionPlan, request: QueryDocument) {
-  if (hexDigest(plan.definition) !== plan.digest) throw Error("INVALID_PLAN");
+  if (executionPlanDigest(plan) !== plan.digest) throw Error("INVALID_PLAN");
   if (
     typeof request.document !== "string" ||
     Buffer.byteLength(request.document) > 32768 ||
diff --git a/src/resource-lock/cli.ts b/src/resource-lock/cli.ts
index 3562ed8..2d220ff 100644
--- a/src/resource-lock/cli.ts
+++ b/src/resource-lock/cli.ts
@@ -1,5 +1,20 @@
 #!/usr/bin/env node
 import { loadQuixosLock } from "./loader.js";
+import { parseQuixosLockDocument } from "./parser.js";
+import { readFile, stat } from "node:fs/promises";
+
+// A trusted fetcher can inspect the root's declared platform pin without
+// following authored import paths or evaluating Nix. The input is a fetched
+// Git blob, not a filesystem tree provided by an author.
+if (process.argv[2] === "--platform-only") {
+  const filename = process.argv[3];
+  if (process.argv.length !== 4 || !filename || (await stat(filename)).size > 1024 * 1024)
+    throw Error("INVALID_PLATFORM_SOURCE_LOCK");
+  const result = parseQuixosLockDocument(await readFile(filename, "utf8"));
+  if (!result.ok || result.document.kind !== "root") throw Error("INVALID_PLATFORM_SOURCE_LOCK");
+  console.log(JSON.stringify({ repository: result.document.quixos.repository, commit: result.document.quixos.commit }));
+  process.exit(0);
+}
 
 const fileName = process.argv[2];
 if (!fileName || process.argv.length !== 3) {
diff --git a/test/candidate-metadata.test.ts b/test/candidate-metadata.test.ts
index 6039c47..112123c 100644
--- a/test/candidate-metadata.test.ts
+++ b/test/candidate-metadata.test.ts
@@ -5,6 +5,7 @@ import { join } from "node:path";
 import { tmpdir } from "node:os";
 import { CandidateMetadataBudget, readCandidateMetadata } from "../src/execution-world/metadata.js";
 import { loadCheckedInstallationCandidate } from "../src/execution-world/candidate.js";
+import { hexDigestAsync } from "../src/execution-world/plan.js";
 
 test(
   "a real checked application can stage its replacement within the default metadata budget",
@@ -21,6 +22,8 @@ test(
       try {
         assert.equal(budget.snapshot().bytes, retained * 2);
         assert.deepEqual(second.reference, first.reference, "Compaction preserves exact checked identity");
+        assert.equal(first.world, await hexDigestAsync(first.graphExecution));
+        assert.equal(second.world, first.world, "Replacement retains the checked execution identity");
         assert.equal(second.graphExecution.kernel, second.kernel, "Graph representation shares the validated program");
         assert.equal(second.graphExecution.queries, second.queries);
         // A deliberately tighter pool admits the serving installation but must
diff --git a/test/evolution.test.ts b/test/evolution.test.ts
index 97ccb97..754fe45 100644
--- a/test/evolution.test.ts
+++ b/test/evolution.test.ts
@@ -3,6 +3,7 @@ import { test } from "node:test";
 import { capabilityId as id, valueType, validateWorkspaceRevision } from "../src/capability-model/index.js";
 import {
   contentDigest,
+  contentDigestAsync,
   planEvolution,
   reviewSemanticMajors,
   runtimeContracts,
@@ -51,6 +52,39 @@ test("hashing is canonical and rejects values outside the persisted JSON contrac
   assert.throws(() => contentDigest(new Date()));
 });
 
+test("cooperative hashing preserves canonical identities and services the event loop", async () => {
+  const sparse = [1, 2, 3];
+  delete sparse[1];
+  const values: unknown[] = [
+    null,
+    false,
+    -0,
+    "中\\n\ud800",
+    sparse,
+    { z: 1, a: { omitted: undefined, b: [false, 1e100] } },
+  ];
+  const shared = { text: "中😀".repeat(22000) };
+  values.push({ first: shared, second: shared });
+  for (const value of values) assert.equal(await contentDigestAsync(value), contentDigest(value));
+  for (const value of [undefined, NaN, Infinity, new Date(), [undefined]])
+    await assert.rejects(contentDigestAsync(value));
+  const cyclic: { next?: unknown } = {};
+  cyclic.next = cyclic;
+  await assert.rejects(contentDigestAsync(cyclic), /cyclic JSON/);
+  const large = Array.from({ length: 50000 }, (_, index) => ({ z: "definition".repeat(8), a: index }));
+  const expected = contentDigest(large);
+  let serviced = false;
+  const timer = setTimeout(() => {
+    serviced = true;
+  }, 0);
+  try {
+    assert.equal(await contentDigestAsync(large), expected);
+    assert.equal(serviced, true, "large verification must let host renewals and RPCs run");
+  } finally {
+    clearTimeout(timer);
+  }
+});
+
 test("a workspace root change and display names do not restart package runtimes", () => {
   const before = makeValidCapabilityWorkspace();
   const after = structuredClone(before);
diff --git a/test/execution-groups.test.ts b/test/execution-groups.test.ts
index 22cc215..938dceb 100644
--- a/test/execution-groups.test.ts
+++ b/test/execution-groups.test.ts
@@ -45,7 +45,7 @@ const prepare = async (workspace: WorkspaceRevision) => {
 test("execution reuse ignores world/source/display changes and unrelated packages", async () => {
   const workspace = await loadReaderWorkspace(),
     original = await prepare(workspace);
-  const before = original.groups()[0]!.executionDigest;
+  const before = (await original.groups())[0]!.executionDigest;
   workspace.sourceRootCommit = "f".repeat(40);
   workspace.packageImports[0]!.displayName = "Renamed";
   workspace.packageImports[0]!.source.commit = "e".repeat(40);
@@ -59,13 +59,13 @@ test("execution reuse ignores world/source/display changes and unrelated package
   const after = await prepare(workspace);
   assert.notEqual(after.plan.digest, original.plan.digest);
   assert.equal(
-    after.groups().find((g) => g.logicalId === workspace.packageImports[0]!.packageId)!.executionDigest,
+    (await after.groups()).find((g) => g.logicalId === workspace.packageImports[0]!.packageId)!.executionDigest,
     before,
   );
   original.environments[workspace.packageImports[0]!.revisionId]!.credentialGeneration = "config:2";
-  assert.notEqual(original.groups()[0]!.executionDigest, before);
+  assert.notEqual((await original.groups())[0]!.executionDigest, before);
   original.environments[workspace.packageImports[0]!.revisionId]!.placement = "module";
-  assert.notEqual(original.groups()[0]!.executionDigest, before);
+  assert.notEqual((await original.groups())[0]!.executionDigest, before);
 });
 
 test("outbound provider changes invalidate consumers while caller changes preserve providers", async () => {
@@ -108,15 +108,15 @@ test("outbound provider changes invalidate consumers while caller changes preser
     dependencies: [{ portId, binding: { kind: "state", slotId: id.slot("slot:document:content") } }],
   };
   const prepared = await prepare(workspace);
-  const values = () => new Map(prepared.groups().map((g) => [g.logicalId, g.executionDigest]));
-  const before = values();
+  const values = async () => new Map((await prepared.groups()).map((g) => [g.logicalId, g.executionDigest]));
+  const before = await values();
   prepared.installation.packages.find((p) => p.revision === "package:reader-runtime@1")!.service!.contentDigest =
     "c".repeat(64);
-  const callerChanged = values();
+  const callerChanged = await values();
   assert.equal(callerChanged.get("provider"), before.get("provider"));
   assert.notEqual(callerChanged.get("package:reader-runtime"), before.get("package:reader-runtime"));
   prepared.installation.packages.find((p) => p.revision === revision)!.service!.contentDigest = "d".repeat(64);
-  const providerChanged = values();
+  const providerChanged = await values();
   assert.notEqual(providerChanged.get("provider"), callerChanged.get("provider"));
   assert.notEqual(providerChanged.get("package:reader-runtime"), callerChanged.get("package:reader-runtime"));
 });
diff --git a/test/execution-world.test.ts b/test/execution-world.test.ts
index 072d13a..ab2047b 100644
--- a/test/execution-world.test.ts
+++ b/test/execution-world.test.ts
@@ -7,7 +7,11 @@ import {
   checkExecutionWorld,
   checkedWorldDigest,
   implementationDigest,
+  clientContractCatalog,
   hexDigest,
+  executionPlanDigest,
+  executionPlanDigestAsync,
+  sealExecutionPlan,
   parsePackageArtifacts,
   artifactPath,
   type PackageArtifacts,
@@ -20,6 +24,54 @@ import { compileKernelProgram } from "../src/execution-world/kernel.js";
 import { loadCompositeWorkspace } from "./composite-fixture.js";
 import { standardNativeBackends } from "../src/execution-world/native-backends.js";
 
+test("sealed runtime plans reuse verified integrity while mutable copies are rechecked", async () => {
+  const workspace = await loadReaderWorkspace();
+  const compiled = compileExecutionPlan(workspace);
+  const plan: ExecutionPlan = JSON.parse(JSON.stringify(compiled));
+  assert.equal(await sealExecutionPlan(plan), true);
+  assert.equal(executionPlanDigest(plan), compiled.digest);
+  assert.equal(await executionPlanDigestAsync(plan), compiled.digest);
+  assert.throws(() => {
+    plan.definition.workspace.sourceRootCommit = "f".repeat(40);
+  }, TypeError);
+  assert.throws(() => {
+    plan.digest = "0".repeat(64);
+  }, TypeError);
+
+  const stringify = JSON.stringify;
+  JSON.stringify = () => {
+    throw Error("Repeated serialization of sealed metadata");
+  };
+  try {
+    assert.equal(executionPlanDigest(plan), compiled.digest);
+    assert.equal(await executionPlanDigestAsync(plan), compiled.digest);
+  } finally {
+    JSON.stringify = stringify;
+  }
+
+  const changed: ExecutionPlan = structuredClone(plan);
+  changed.definition.workspace.sourceRootCommit = "f".repeat(40);
+  Object.freeze(changed);
+  assert.notEqual(executionPlanDigest(changed), plan.digest);
+  assert.notEqual(await executionPlanDigestAsync(changed), plan.digest);
+  assert.equal(await sealExecutionPlan(changed), false, "shallow freezing is not an integrity proof");
+
+  const resigned: ExecutionPlan = structuredClone(plan);
+  resigned.definition.workspace.sourceRootCommit = "e".repeat(40);
+  resigned.digest = executionPlanDigest(resigned);
+  assert.equal(await sealExecutionPlan(resigned), true);
+  assert.notEqual(executionPlanDigest(resigned), plan.digest);
+  workspace.sourceRootCommit = "d".repeat(40);
+  assert.equal(workspace.sourceRootCommit, "d".repeat(40), "sealing owned JSON leaves compiler inputs editable");
+});
+
+test("runtime plan sealing rejects accessor-backed metadata", async () => {
+  const plan: ExecutionPlan = compileExecutionPlan(await loadReaderWorkspace());
+  assert.equal(await sealExecutionPlan(Object.create(plan)), false, "inherited integrity fields cannot be sealed");
+  Object.defineProperty(plan.definition, "codec", { get: () => "camino-execution-plan-v1", enumerable: true });
+  await assert.rejects(sealExecutionPlan(plan), /INVALID_PLAN_JSON/);
+});
+
 test("optional targets close over calls into another package", async () => {
   const workspace = await loadCompositeWorkspace();
   const before = compileExecutionPlan(workspace).definition.operations.find(
@@ -385,7 +437,14 @@ test("public reflection contains nominal contracts and callable descriptors with
     components: [],
     routes: {},
   };
-  const snapshot = publicDefinitionSnapshot(plan, installation);
+  const kernel = compileKernelProgram(plan) as import("../src/execution-world/inspection.js").InspectionKernel;
+  const catalog = await clientContractCatalog(
+    plan,
+    installation,
+    installation.packages.map((pkg) => pkg.revision),
+    kernel,
+  );
+  const snapshot = await publicDefinitionSnapshot(plan, kernel, catalog);
   assert.ok(snapshot.rows.interfaces.length);
   assert.ok(snapshot.rows.queries.length);
   assert.ok(snapshot.rows.conformances.length);
@@ -400,5 +459,19 @@ test("public reflection contains nominal contracts and callable descriptors with
     assert.ok(!publicText.includes('"' + privateKey + '"'), privateKey);
   assert.ok(publicText.includes('"descriptor"'));
   assert.ok(publicText.includes('"scope":"class"'));
-  assert.equal(snapshot.id, publicDefinitionSnapshot(plan, installation).id);
+  assert.equal(snapshot.id, (await publicDefinitionSnapshot(plan, kernel, catalog)).id);
+  // Historical checked availability must survive a newer host compiler. If
+  // reflection silently regenerates the Kernel, this evidence disappears.
+  const historical = structuredClone(kernel);
+  const installed = historical.operations.find((operation) => !operation.unsupported)!;
+  assert.ok(installed);
+  installed.unsupported = "CHECKED_HISTORICAL_UNSUPPORTED";
+  const historicalCatalog = await clientContractCatalog(
+    plan,
+    installation,
+    installation.packages.map((pkg) => pkg.revision),
+    historical,
+  );
+  const historicalSnapshot = await publicDefinitionSnapshot(plan, historical, historicalCatalog);
+  assert.match(JSON.stringify(historicalSnapshot.rows.conformances), /CHECKED_HISTORICAL_UNSUPPORTED/);
 });
diff --git a/test/presentations.test.ts b/test/presentations.test.ts
index b9d16c5..29a7d34 100644
--- a/test/presentations.test.ts
+++ b/test/presentations.test.ts
@@ -249,13 +249,13 @@ test("checked component-only artifacts install without a service and reject miss
     assert.ok(installation.routes[installation.components[0]!.url]);
     assert.equal(JSON.stringify(installation.components).includes(root), false);
     assert.equal(JSON.stringify(installation.components).includes("slot:"), false);
-    const catalog = clientContractCatalog(plan, installation, [pkg.revision]);
+    const catalog = await clientContractCatalog(plan, installation, [pkg.revision]);
     assert.equal(catalog.presentations[0]!.component, "component:card");
     assert.equal(catalog.components[0]!.subject, "interface:Data@1");
     assert.equal(JSON.stringify(catalog).includes(root), false);
     assert.equal(JSON.stringify(catalog).includes("bindingSchema"), false);
-    assert.throws(() => clientContractCatalog(plan, installation, ["absent"]), /UNINSTALLED_PACKAGE/);
-    assert.throws(
+    await assert.rejects(() => clientContractCatalog(plan, installation, ["absent"]), /UNINSTALLED_PACKAGE/);
+    await assert.rejects(
       () => clientContractCatalog(plan, { ...installation, plan: "bad" }, [pkg.revision]),
       /CATALOG_PLAN_MISMATCH/,
     );
@@ -268,14 +268,16 @@ test("checked component-only artifacts install without a service and reject miss
       compileKernelProgram(plan) as InspectionKernel,
     );
     try {
-      assert.throws(() => prepared.select(["absent"]), /UNINSTALLED_PACKAGE/);
+      await assert.rejects(() => prepared.select(["absent"]), /UNINSTALLED_PACKAGE/);
       assert.equal(scope.bytes, 0, "Unknown requests do not allocate compiler metadata");
-      assert.deepEqual(prepared.select([pkg.revision]), catalog);
+      const [first, coalesced] = await Promise.all([prepared.select([pkg.revision]), prepared.select([pkg.revision])]);
+      assert.deepEqual(first, catalog);
+      assert.equal(first.operations, coalesced.operations, "Concurrent preparation shares one metadata reservation");
       const retained = scope.bytes;
       assert.ok(retained > 0);
       assert.ok(retained < 32 * 1024 * 1024, "Small catalogs retain a proportional metadata charge");
-      const full = prepared.select([pkg.revision]);
-      const empty = prepared.select([]);
+      const full = await prepared.select([pkg.revision]);
+      const empty = await prepared.select([]);
       assert.deepEqual(empty.components, []);
       assert.deepEqual(empty.presentations, []);
       assert.deepEqual(empty.moduleBindings, []);
@@ -290,14 +292,14 @@ test("checked component-only artifacts install without a service and reject miss
         },
       });
       try {
-        assert.deepEqual(prepared.select([pkg.revision]), full);
+        assert.deepEqual(await prepared.select([pkg.revision]), full);
         assert.equal(scope.bytes, retained, "Package projections do not accumulate cache entries");
       } finally {
         Object.defineProperty(plan, "definition", { configurable: true, value: definition });
       }
       prepared.close();
       assert.equal(scope.bytes, 0);
-      assert.throws(() => prepared.select([pkg.revision]), /CANDIDATE_METADATA_CLOSED/);
+      await assert.rejects(() => prepared.select([pkg.revision]), /CANDIDATE_METADATA_CLOSED/);
     } finally {
       prepared.close();
       scope.release();
@@ -305,7 +307,7 @@ test("checked component-only artifacts install without a service and reject miss
     const tight = new CandidateMetadataBudget({ bytes: 1000, ownerBytes: 1000, candidates: 1 });
     const tightScope = tight.acquire("catalog-test");
     const refused = createClientContractCatalog(plan, installation, tightScope);
-    assert.throws(() => refused.select([pkg.revision]), /CANDIDATE_METADATA_LIMIT/);
+    await assert.rejects(() => refused.select([pkg.revision]), /CANDIDATE_METADATA_LIMIT/);
     assert.equal(tightScope.bytes, 0);
     refused.close();
     tightScope.release();
diff --git a/test/source-closure.test.ts b/test/source-closure.test.ts
index 4fb8c3e..3cb19d1 100644
--- a/test/source-closure.test.ts
+++ b/test/source-closure.test.ts
@@ -172,6 +172,27 @@ test("exact source closure recovers through explicitly selected bundles, preserv
     directory: path.join(temporary, "b"),
   });
   assert.notEqual(a.workspaceId, b.workspaceId);
+  const assigned = "f8f2f8a3-328c-45a2-847a-31869ad28ce7";
+  const c = await prepareDevelopmentSources({
+    source: root,
+    cacheDirectory: directory,
+    directory: path.join(temporary, "assigned"),
+    workspaceId: assigned,
+  });
+  assert.equal(c.workspaceId, assigned);
+  assert.equal(
+    JSON.parse(await readFile(path.join(c.directory, ".quixos/resource-graph.json"), "utf8")).workspaceId,
+    assigned,
+  );
+  await assert.rejects(
+    prepareDevelopmentSources({
+      source: root,
+      cacheDirectory: directory,
+      directory: path.join(temporary, "invalid"),
+      workspaceId: "not-a-workspace",
+    }),
+    /Workspace UUID/,
+  );
   const aRoot = path.join(a.directory, "root"),
     bRoot = path.join(b.directory, "root");
   assert.equal((await exec("git", ["remote", "get-url", "origin"], { cwd: aRoot })).stdout.trim(), root.repository);