Fix review findings: validate the hooks cap, integer read caps, doc drift, config plumb-through test

A Codex review pass on the draft caught four real gaps and two solid
suggestions; all addressed except one pushed back on the merits:

- hooks-claude/hooks-codex: stderrSummaryMaxChars was the one new knob
  with NO range validation — a negative/NaN cap would silently
  misbehave inside slice(). Both bridges now assert a positive integer
  at the TOP of apply() (before the config-file parse's early return,
  so a bad value fails the load loudly), with rejection tests.
- tool-fs: the read caps count lines/chars/bytes, so positive-FINITE
  was too loose (a fractional readLimit would flow into windowing
  arithmetic and the schema description). All four now require a
  positive integer, matching tool-web's cap.
- Doc drift the gates cannot catch: tool-web's README tools table
  still named WEB_SEARCH_MAX_RESULTS as the mechanism; compact-basic's
  README/module doc and the compaction-capability-seam RFC still
  described estimation as fixed char/4 rather than the charsPerToken
  default.
- subagent-acp: the dispose graces were tested only at the
  startAcpRun level, so a regression that stopped threading plugin
  config into AcpRunSpec would have survived. A provider-path test now
  drives the trap-escalation scenario through ctx.subagents.start with
  small config graces and bounds dispose at 4s.

Pushed back on: converting compact-basic's charsPerToken to a
schemastery field. The package's whole config is deliberately
hand-rolled (resolveConfig, every threshold REQUIRED with no default —
a documented design posture); one schemastery field beside it would be
incoherent. The knob is cordis.yml-reachable, defaulted, and validated,
which is what the convention requires; migrating the package to
schemastery wholesale is pre-existing config-surface hygiene out of
this change's scope.

docs/rfc/implemented/feature/2026-06-18-compaction-capability-seam.md

@@ -17,7 +17,7 @@ Two forces shape the design. First, compaction is **swappable**: token counting
 Per the [capability-seams RFC](../../implemented/architecture/2026-06-13-capability-seams.md), compaction ships as separate packages so the contract, the algorithm, and (later) the consumer surface evolve independently:
 
 1. **Interface** — `@deepseek-ai/dsh-compact`: an abstract `CompactService` owning the `ctx.compact` key, the `CompactionResult` vocabulary, and the `compact/*` session events. It declares `compactIfNeeded()` and `compactRegion()` as **abstract** — the contract states *what* compaction does, not *how*.
-2. **Implementation** — `@deepseek-ai/dsh-compact-basic`: a concrete `BasicCompactService` that owns the entire algorithm — token estimation (char/4 + per-block overhead), the tail→head retention walk, summarization via `ctx.llm.stream()`, the surface replacement, the lock, and the `agent/pre-step` auto-compaction listener. A tokenizer-based or template-based backend is a sibling package (or a subclass overriding the two protected estimation/summarization hooks).
+2. **Implementation** — `@deepseek-ai/dsh-compact-basic`: a concrete `BasicCompactService` that owns the entire algorithm — token estimation (chars per token — the `charsPerToken` config, default 4 — + per-block overhead), the tail→head retention walk, summarization via `ctx.llm.stream()`, the surface replacement, the lock, and the `agent/pre-step` auto-compaction listener. A tokenizer-based or template-based backend is a sibling package (or a subclass overriding the two protected estimation/summarization hooks).
 3. **Consumer** — deferred. A `/compact` tool and slash command will `inject: ['compact']` and call the contract; they are intentionally out of scope here so the seam settles first.
 
 ### The contract depends on `dsh-session` and `dsh-llm` — a deliberate deviation

packages/compact/compact-basic/README.md

@@ -1,6 +1,6 @@
 # @deepseek-ai/dsh-compact-basic
 
-The **basic compaction backend**: a `BasicCompactService` implementing the `@deepseek-ai/dsh-compact` seam with a char/4 token heuristic, token-budget retention, and summarization routed through the agent request pipeline.
+The **basic compaction backend**: a `BasicCompactService` implementing the `@deepseek-ai/dsh-compact` seam with a chars-per-token heuristic (the `charsPerToken` config, default 4), token-budget retention, and summarization routed through the agent request pipeline.
 
 This is the implementation tier of the compaction capability — see the [interface package](../compact/README.md) for the seam and the [capability-seam RFC](../../../docs/rfc/implemented/feature/2026-06-18-compaction-capability-seam.md) for the design.
 
@@ -8,7 +8,7 @@ This is the implementation tier of the compaction capability — see the [interf
 
 The abstract contract states only WHAT compaction does; this backend owns every HOW decision:
 
-- **Token estimation** — `estimateContentTokens()`: char/4 with per-block structural overhead (`text`/`reasoning` = `ceil(len/4) + 4`, `tool-call` from name + arguments, `tool-result` recursive, `image` = 85, unknown blocks via JSON length).
+- **Token estimation** — `estimateContentTokens()`: chars divided by the `charsPerToken` config (default 4) with per-block structural overhead (`text`/`reasoning` = `ceil(len/charsPerToken) + 4`, `tool-call` from name + arguments, `tool-result` recursive, `image` = 85, unknown blocks via JSON length).
 - **Retention policy** — `compactIfNeeded()` walks the surface nodes tail→head summing per-node token estimates, and retains the smallest tail-run of WHOLE units (a closed step, or a single no-step node such as a pre-step `user/message` or inter-step `steering/message`) whose total reaches `retainTokens`; everything older is compacted. Retention is **turn-agnostic** — turn boundaries play no role, so a single runaway turn that alone exceeds the window compacts its OWN early closed steps rather than being retained verbatim (the failure mode that motivated dropping turn-protection: a tool-heavy turn must stay compactable or the harness dies exactly when compaction is needed). The only structural guard is **tool-pairing balance**: the compacted region's edges are balanced cuts on the surface (no unanswered tool-call crosses either edge), so it never splits a step's `assistant/message` tool-calls from their `tool/result`s. When the only compactable content left is an un-splittable open tail step, it declines (returns `null`) and retries once an older step closes. **Single-unit overflow is out of scope, by design**: if one retained unit (a single closed step, or a large pasted `user/message`) ALONE exceeds the budget, compaction cannot help and the call may go out over-budget — bounding an individual unit's size is a separate concern. `compactRegion()` enforces tool-pairing balance strictly, throwing on a boundary that would split a step. `dsh-session` exports `isToolPairingBalanced` for the check.
 - **Dynamic convergence** — no static summary-length config pretends to bound what the model will write. If framing/estimator/system overhead leaves the compacted surface above threshold, `compactIfNeeded()` re-compacts the head checkpoint up to `compactionRetries` extra times; if it still cannot get below threshold, it throws. A summary whose estimated stored size is not smaller than the shadowed content fails closed before it mutates the surface.
 - **Summarization** — `summarize()`: a `GenerateOptions` request assembled via `BlockAssembler` with a fixed system prompt that asks for a structured checkpoint (Primary Request and Intent · Key Technical Concepts · Files and Code · Errors and Fixes · Pending Tasks · Current Work · Next Step · Critical Context), every section mandatory, exact paths/commands/identifiers preserved. The request runs through the `agent/request` waterfall before `ctx.llm.stream()`, so router agents that choose the concrete model there also route compaction summaries. `maxTokens` is the provider-side generation cap; only text blocks from the model's reply are kept before the checkpoint is stored (reasoning is dropped so private chain-of-thought never leaks into the durable summary, and a stray `tool-call` is dropped so the synthesized `user/message` summary cannot land an orphaned call with no matching `tool-result`). The compacted region is flattened to a plain-text transcript first: text and reasoning contribute their text, and every non-text block (image, tool-call, tool-result, plugin-added types) contributes a type-tagged placeholder (`[image]`, `[tool-call: name(args)]`, …) so the summarizer is told what existed rather than silently dropping it.

packages/compact/compact-basic/src/index.ts

@@ -2,7 +2,8 @@
  * `BasicCompactService`: the first implementation of the
  * `@deepseek-ai/dsh-compact` seam. It owns the entire compaction strategy:
  *
- * - **Token estimation** — char/4 heuristic with per-block structural overhead.
+ * - **Token estimation** — chars/`charsPerToken` heuristic (config, default 4)
+ *   with per-block structural overhead.
  * - **Retention policy** — walk surface nodes tail→head, keep recent nodes up
  *   to a token budget, compact everything older. The cutoff is snapped forward
  *   to the next balanced tool-pairing boundary so a compacted region never

packages/fs/tool-fs/src/index.ts

@@ -66,10 +66,10 @@ export const Config: z<Config> = z.object({
 /** The shape after schemastery applied the defaults. */
 type ResolvedConfig = Required<Config>
 
-/** A read cap must be a positive finite number to bound output and memory. */
-function assertPositiveFinite(name: string, value: number): void {
-  if (!Number.isFinite(value) || value <= 0) {
-    throw new Error(`tool-fs: ${name} must be a positive finite number`)
+/** Every read cap counts lines/chars/bytes — a positive integer, or windowing arithmetic misbehaves silently. */
+function assertPositiveInteger(name: string, value: number): void {
+  if (!Number.isInteger(value) || value < 1) {
+    throw new Error(`tool-fs: ${name} must be a positive integer`)
   }
 }
 
@@ -77,10 +77,10 @@ function assertPositiveFinite(name: string, value: number): void {
 export function apply(ctx: Context, config: Config): void {
   // schemastery (Config) has already filled every defaulted field.
   const resolved = config as ResolvedConfig
-  assertPositiveFinite('readLimit', resolved.readLimit)
-  assertPositiveFinite('readMaxLineLength', resolved.readMaxLineLength)
-  assertPositiveFinite('readMaxBytes', resolved.readMaxBytes)
-  assertPositiveFinite('readStreamMinSize', resolved.readStreamMinSize)
+  assertPositiveInteger('readLimit', resolved.readLimit)
+  assertPositiveInteger('readMaxLineLength', resolved.readMaxLineLength)
+  assertPositiveInteger('readMaxBytes', resolved.readMaxBytes)
+  assertPositiveInteger('readStreamMinSize', resolved.readStreamMinSize)
   applyReadTool(ctx, {
     limit: resolved.readLimit,
     maxLineLength: resolved.readMaxLineLength,

packages/fs/tool-fs/tests/tools.spec.ts

@@ -547,15 +547,16 @@ describe('read caps are plugin config', () => {
 
   it.each([
     ['readLimit', { readLimit: 0 }],
+    ['readLimit', { readLimit: 2.5 }],
     ['readMaxLineLength', { readMaxLineLength: -1 }],
     ['readMaxBytes', { readMaxBytes: Number.NaN }],
     ['readStreamMinSize', { readStreamMinSize: 0 }],
-  ] as const)('rejects a non-positive %s at load', async (name, config) => {
+  ] as const)('rejects a non-positive or fractional %s at load', async (name, config) => {
     const ctx = new Context()
     await ctx.plugin(SystemPrompt)
     await ctx.plugin(ToolRegistry)
     await ctx.plugin(FakeFs)
-    await expect(ctx.plugin(ToolFs, config)).rejects.toThrow(new RegExp(`tool-fs: ${name} must be a positive finite number`))
+    await expect(ctx.plugin(ToolFs, config)).rejects.toThrow(new RegExp(`tool-fs: ${name} must be a positive integer`))
   })
 
   it('has no default export (namespace plugin export shape)', () => {

packages/hooks/hooks-claude/src/index.ts

@@ -95,7 +95,18 @@ function nextHandlerId(point: string): string {
 /** The `{kind:'plugin'}` source stamped on every context this bridge injects. */
 const PLUGIN_SOURCE: MessageSource = { kind: 'plugin', plugin: 'hooks-claude' }
 
+/** The summary cap bounds a persisted event field — a positive integer or the slice misbehaves silently. */
+function assertPositiveInteger(name: string, value: number): void {
+  if (!Number.isInteger(value) || value < 1) {
+    throw new Error(`hooks-claude: ${name} must be a positive integer`)
+  }
+}
+
 export function apply(ctx: Context, config: Config): void {
+  // Validate the cap BEFORE the config-file parse: a bad value must fail the
+  // load loudly, not be skipped by the parse-failure early return.
+  const stderrSummaryMaxChars = config.stderrSummaryMaxChars ?? 500
+  assertPositiveInteger('stderrSummaryMaxChars', stderrSummaryMaxChars)
   // --- Parse the config ONCE at load. A read/parse failure is contained: the
   // bridge logs and registers nothing rather than crashing boot (a typo'd path
   // must not take the agent down). ---
@@ -116,7 +127,6 @@ export function apply(ctx: Context, config: Config): void {
   }
 
   const defaultTimeoutMs = config.defaultTimeoutMs ?? 600_000
-  const stderrSummaryMaxChars = config.stderrSummaryMaxChars ?? 500
 
   /**
    * Run every command hook configured for `point` whose matcher selects

packages/hooks/hooks-claude/tests/coverage.spec.ts

@@ -142,6 +142,16 @@ describe('hooks-claude coverage — empty/no-op outcomes and no-agent paths', ()
     expect(res?.type === 'hook/result' && res.data.stderrSummary?.length).toBe(501) // default 500-char cap + ellipsis
   })
 
+  it('rejects a non-positive or fractional stderrSummaryMaxChars at load', async () => {
+    const d = dir()
+    const path = hooks(d, {})
+    for (const bad of [0, -5, 1.5, Number.NaN]) {
+      const adapter = new MockAdapter([])
+      await expect(harness(path, adapter, { stderrSummaryMaxChars: bad }))
+        .rejects.toThrow(/hooks-claude: stderrSummaryMaxChars must be a positive integer/)
+    }
+  })
+
   it('the stderr summary cap is plugin config (stderrSummaryMaxChars)', async () => {
     const d = dir()
     const s = sh(d, 'long.sh', '#!/usr/bin/env bash\nprintf "x%.0s" {1..600} >&2\nexit 2\n')

packages/hooks/hooks-codex/src/index.ts

@@ -68,7 +68,18 @@ function nextHandlerId(point: string): string {
 
 const PLUGIN_SOURCE: MessageSource = { kind: 'plugin', plugin: 'hooks-codex' }
 
+/** The summary cap bounds a persisted event field — a positive integer or the slice misbehaves silently. */
+function assertPositiveInteger(name: string, value: number): void {
+  if (!Number.isInteger(value) || value < 1) {
+    throw new Error(`hooks-codex: ${name} must be a positive integer`)
+  }
+}
+
 export function apply(ctx: Context, config: Config): void {
+  // Validate the cap BEFORE the config-file parse: a bad value must fail the
+  // load loudly, not be skipped by the parse-failure early return.
+  const stderrSummaryMaxChars = config.stderrSummaryMaxChars ?? 500
+  assertPositiveInteger('stderrSummaryMaxChars', stderrSummaryMaxChars)
   let parsed: CodexHookConfig = {}
   try {
     const raw: unknown = JSON.parse(readFileSync(config.configPath, 'utf8'))
@@ -83,7 +94,6 @@ export function apply(ctx: Context, config: Config): void {
   }
 
   const defaultTimeoutMs = config.defaultTimeoutMs ?? 600_000
-  const stderrSummaryMaxChars = config.stderrSummaryMaxChars ?? 500
   const model = config.model ?? ''
 
   async function runPoint(

packages/hooks/hooks-codex/tests/coverage.spec.ts

@@ -207,6 +207,16 @@ describe('hooks-codex coverage — decision mapping paths', () => {
     expect(res?.type === 'hook/result' && res.data.stderrSummary?.length).toBe(501) // default 500-char cap + ellipsis
   })
 
+  it('rejects a non-positive or fractional stderrSummaryMaxChars at load', async () => {
+    const d = dir()
+    hooks(d, {})
+    for (const bad of [0, -5, 1.5, Number.NaN]) {
+      const adapter = new MockAdapter([])
+      await expect(harness(join(d, 'hooks.json'), adapter, { stderrSummaryMaxChars: bad }))
+        .rejects.toThrow(/hooks-codex: stderrSummaryMaxChars must be a positive integer/)
+    }
+  })
+
   it('the stderr summary cap is plugin config (stderrSummaryMaxChars)', async () => {
     const d = dir()
     hooks(d, { PreToolUse: [{ hooks: [{ type: 'command', command: sh(d, 'l.sh', '#!/usr/bin/env bash\nprintf "x%.0s" {1..600} >&2\nexit 2\n') }] }] })

packages/subagent/subagent-acp/tests/subagent-acp.spec.ts

@@ -398,6 +398,37 @@ describe('dsh-subagent-acp', () => {
     await run.dispose()
   })
 
+  it('plugin-config dispose graces reach the run (SIGKILL escalation through the provider)', async () => {
+    // Same trap scenario as the direct startAcpRun escalation test, but the
+    // graces arrive via the PLUGIN CONFIG through the registered provider — so a
+    // regression that stops threading config into AcpRunSpec (falling back to
+    // the 6s/3s defaults) blows past the 4000ms bound and fails loud.
+    const tmp = mkdtempSync(join(tmpdir(), 'acp-cfg-trap-'))
+    const ready = join(tmp, 'trap-armed')
+    try {
+      const ctx = new Context()
+      await ctx.plugin(SubagentService)
+      await ctx.plugin(acp, {
+        providerName: 'acp',
+        command: process.execPath,
+        args: ['--import', tsxLoader, mockServer],
+        permission: 'reject',
+        env: { MOCK_TRAP_SIGTERM: '1', MOCK_TEXT: 'x', MOCK_READY_FILE: ready, TSX_TSCONFIG_PATH: repoTsconfig },
+        disposeEofGraceMs: 150,
+        disposeGraceMs: 150,
+      })
+      const run = ctx.subagents.start('acp', { prompt: [{ type: 'text', text: 'p' }], parent: fakeParent })
+      await waitForFile(ready)
+      await expect(Promise.race([
+        run.dispose(),
+        new Promise((_r, reject) => { setTimeout(() => { reject(new Error('dispose did not return — config graces not threaded to the run')) }, 4000) }),
+      ])).resolves.toBeUndefined()
+      await ctx.fiber.dispose()
+    } finally {
+      rmSync(tmp, { recursive: true, force: true })
+    }
+  })
+
   it('rejects a non-positive dispose grace at load', async () => {
     for (const bad of [{ disposeEofGraceMs: 0 }, { disposeGraceMs: -1 }, { disposeEofGraceMs: Number.NaN }]) {
       const ctx = new Context()

packages/web/tool-web/README.md

@@ -8,7 +8,7 @@ Each tool is registered independently; a product that wants only one disables th
 
 | Tool | Args | Behavior |
 |---|---|---|
-| `web_search` | `query` (string) | Discovery. Returns an optional answer plus source URLs. `max_results` is **not** model-facing — the tool sets the bound (`WEB_SEARCH_MAX_RESULTS = 8`) and passes it to the seam. |
+| `web_search` | `query` (string) | Discovery. Returns an optional answer plus source URLs. `max_results` is **not** model-facing — the tool sets the bound (the `searchMaxResults` config, default 8) and passes it to the seam. |
 | `web_fetch` | `url` (string), `timeout_ms` (number, optional) | Retrieves a specific URL. HTML bodies are rendered to markdown-ish text; text bodies pass through. A non-2xx status is reported, not an error. |
 
 ## Config