diff --git a/packages/oracles/oracle-gaps/check.mjs b/packages/oracles/oracle-gaps/check.mjs
index a1139a1..1a63f92 100644
--- a/packages/oracles/oracle-gaps/check.mjs
+++ b/packages/oracles/oracle-gaps/check.mjs
@@ -1256,10 +1256,132 @@ export default async (env) => {
       }
     } finally {
       for (const copy of copies) globalThis.__oracleGapsCopies.delete(copy)
+      retireCopies(context, copies)
       rmSync(capture, { force: true })
     }
   }
 
+  /**
+   * Removes a batch's copies from Vitest's state and from Vite's module
+   * graphs once their units are plain data (the register's C entry: the gap
+   * CLI keeps no Vitest or Vite state for a mutant copy after the copy's
+   * results are plain data). Each copy is a new file. Vitest keeps its path
+   * in `filesMap` and `pathsSet`, and the file and test tasks it ran in
+   * `idMap`, and Vite keeps a module node, with its transform, per copy.
+   * Vitest's `clearFiles` replaces the path's file entry only, and leaves
+   * `pathsSet` and the test tasks, so it is not used: each entry is removed.
+   * Every map touched is guarded, and a Vitest or Vite whose shape changes
+   * throws here rather than leaking quietly. During a run, Vitest holds the
+   * run's copies until it ends, so the in-run peak scales with the batch's
+   * share of copies, not with the suite.
+   */
+  function retireCopies(context, copies) {
+    const { filesMap, idMap, pathsSet } = context.state ?? {}
+    if (
+      !(filesMap instanceof Map) ||
+      !(idMap instanceof Map) ||
+      !(pathsSet instanceof Set)
+    )
+      throw new Error(
+        `oracle-gaps: this Vitest keeps no filesMap, idMap, or pathsSet in its state, so a check cannot retire its copies`,
+      )
+    const gone = new Set(copies)
+    for (const [id, task] of idMap)
+      if (gone.has(task.file?.filepath ?? task.filepath)) idMap.delete(id)
+    for (const copy of copies) {
+      filesMap.delete(copy)
+      pathsSet.delete(copy)
+    }
+    const modulesRemoved = retireModules(context.getRootProject().vite, gone)
+    retiredEntries(context, copies, modulesRemoved)
+  }
+
+  /**
+   * Removes the copies' module nodes from every environment's Vite graph.
+   * Each node is invalidated through Vite's API (which drops its transform),
+   * then removed from the graph's id, url, etag, and file maps, and from its
+   * neighbours' import sets. The graph's map shapes are guarded.
+   */
+  function retireModules(server, gone) {
+    const environments = viteEnvironments(server)
+    let removed = 0
+    for (const environment of environments) {
+      const graph = environment.moduleGraph
+      const {
+        urlToModuleMap,
+        idToModuleMap,
+        etagToModuleMap,
+        fileToModulesMap,
+      } = graph ?? {}
+      if (
+        !(urlToModuleMap instanceof Map) ||
+        !(idToModuleMap instanceof Map) ||
+        !(etagToModuleMap instanceof Map) ||
+        !(fileToModulesMap instanceof Map) ||
+        typeof graph.invalidateModule !== `function`
+      )
+        throw new Error(
+          `oracle-gaps: this Vite's module graph has no id, url, etag, or file maps, so a check cannot retire its copies`,
+        )
+      for (const copy of gone) {
+        for (const mod of fileToModulesMap.get(copy) ?? []) {
+          removed += 1
+          graph.invalidateModule(mod)
+          for (const imported of mod.importedModules)
+            imported.importers.delete(mod)
+          for (const importer of mod.importers)
+            importer.importedModules.delete(mod)
+          idToModuleMap.delete(mod.id)
+          urlToModuleMap.delete(mod.url)
+          if (mod.etag !== undefined) etagToModuleMap.delete(mod.etag)
+        }
+        fileToModulesMap.delete(copy)
+      }
+    }
+    return removed
+  }
+
+  // Vite's environments, each with its module graph. A Vite that exposes none
+  // would make the module step a silent no-op, so it throws here.
+  function viteEnvironments(server) {
+    const environments = Object.values(server?.environments ?? {})
+    if (environments.length === 0 || environments.some((e) => !e?.moduleGraph))
+      throw new Error(
+        `oracle-gaps: this Vitest exposes no Vite environments with module graphs, so a check cannot retire its copies' module nodes`,
+      )
+    return environments
+  }
+
+  // The test hook (ORACLE_GAPS_TEST_RETENTION, a file path): after each
+  // batch's copies are retired, one line counts the state entries and module
+  // nodes that still name a retired copy. The retention law reads it: each
+  // count is 0.
+  function retiredEntries(context, copies, modulesRemoved) {
+    const file = process.env.ORACLE_GAPS_TEST_RETENTION
+    if (!file) return
+    const gone = new Set(copies)
+    const named = (path) => gone.has(path)
+    const { filesMap, idMap, pathsSet } = context.state
+    let tasks = 0
+    for (const task of idMap.values())
+      if (named(task.file?.filepath ?? task.filepath)) tasks += 1
+    let nodes = 0
+    for (const environment of viteEnvironments(context.getRootProject().vite))
+      for (const copy of gone)
+        nodes += environment.moduleGraph.fileToModulesMap.get(copy)?.size ?? 0
+    appendFileSync(
+      file,
+      `${JSON.stringify({
+        copies: copies.length,
+        filesMap: [...filesMap.keys()].filter(named).length,
+        pathsSet: [...pathsSet].filter(named).length,
+        idMap: tasks,
+        moduleNodes: nodes,
+        modulesRemoved,
+      })}\n`,
+    )
+  }
+
   async function check(options, store, log = console.error) {
     const authored = options.mutants ? loadAuthored(options.mutants) : []
     seedVariable = `${options.envPrefix}_SEED`
diff --git a/packages/oracles/oracle-gaps/gap-report-oracle.property.test.mjs b/packages/oracles/oracle-gaps/gap-report-oracle.property.test.mjs
index 86cc8cc..5fe7342 100644
--- a/packages/oracles/oracle-gaps/gap-report-oracle.property.test.mjs
+++ b/packages/oracles/oracle-gaps/gap-report-oracle.property.test.mjs
@@ -647,13 +647,25 @@ function runCli(dir, files, how = {}) {
   writeFixture(dir, files)
   const before = new Set(filesUnder(dir))
   const { args, out } = cliArgs(dir, files, how)
+  // The retention hook (ORACLE_GAPS_TEST_RETENTION): one line per batch,
+  // written beside the run's own temporary files, not in the package.
+  const hook = join(
+    mkdtempSync(join(tmpdir(), `gap-retention-`)),
+    `retention.jsonl`,
+  )
   const child = spawnSync(process.execPath, args, {
     cwd: repo,
     encoding: `utf8`,
     timeout: 300_000,
     maxBuffer: 64 * 1024 * 1024,
-    env: cleanEnv(),
+    env: { ...cleanEnv(), ORACLE_GAPS_TEST_RETENTION: hook },
   })
+  const retention = existsSync(hook)
+    ? readFileSync(hook, `utf8`)
+        .split(`\n`)
+        .filter(Boolean)
+        .map((line) => JSON.parse(line))
+    : []
   const run = readRun(
     dir,
     out,
@@ -667,7 +679,7 @@ function runCli(dir, files, how = {}) {
     .split(`\n`)
     .find((line) => line.startsWith(`  replay: `))
     ?.slice(`  replay: `.length)
-  return { ...run, strayWrites: strays(dir, before), replay }
+  return { ...run, strayWrites: strays(dir, before), replay, retention }
 }
 
 /**
@@ -1600,10 +1612,11 @@ async function driver(plan, observe) {
       cli: plan.cliPath === `spaced` ? copy : here,
       ...configArgs(plan),
     }
-    const { replay, ...cli } = runCli(dir, files, how)
+    const { replay, retention, ...cli } = runCli(dir, files, how)
     // How many units were computed or reused says how the result was
     // produced, not what it is, so it is not observed.
     observe(`cli`, { ...cli, evidence: undefined })
+    observe(`retention`, retention)
     // A failing owner's replay, run as the author would run it (law 3).
     if (plan.fault === `brokenOwner`)
       observe(`replay`, { command: replay, ran: replayed(dir, replay) })
@@ -2170,6 +2183,25 @@ function check(plan, observations, expected) {
     )
   const stream = streamBreach(`cli`, cli, expected, plan)
   if (stream) return stream
+  // Bounded retention (the register's C entry): once a batch's copies are
+  // retired, Vitest's filesMap, pathsSet, and idMap and Vite's module graph
+  // name none of them, so each count the hook reports is 0.
+  const retention = observations.find(
+    (o) => o.checkpoint === `retention`,
+  )?.value
+  const held = (retention ?? []).find(
+    (line) => line.filesMap + line.pathsSet + line.idMap + line.moduleNodes > 0,
+  )
+  if (held)
+    return violation(
+      `retention`,
+      `a batch left its retired copies in Vitest or Vite state: ${JSON.stringify(held)}`,
+      `bounded retention`,
+      {
+        actual: held,
+        expected: { filesMap: 0, pathsSet: 0, idMap: 0, moduleNodes: 0 },
+      },
+    )
   // Through the daemon, each check streams the same kinds of line, and a
   // completed one ends with its done line (law 15). The state of each step
   // differs, so its verdict and counts are judged by law 9's comparison.