Merge branch 'codex/invariant-package-registration-gate' into codex/package-invariant-checks

# Conflicts:
#	.agents/notes/implemented/architecture/2026-07-19-package-invariant-runtime-contracts.i18n.yaml
#	.agents/notes/implemented/architecture/2026-07-19-package-invariant-runtime-contracts.md
#	.agents/notes/implemented/architecture/2026-07-19-package-invariant-runtime-contracts.zh.md
#	.agents/notes/implemented/architecture/2026-07-19-package-owned-invariant-service.i18n.yaml
#	docs/rfc/INDEX.md
#	packages/AGENTS.md

packages/tasks/README.md

@@ -1,6 +1,6 @@
 # tasks/ — background task capability family
 
-The shared home for background-task ids, owner isolation, reads, cancellation, waiting, and completion notices. Bash, subagents, and future long-running tools use one model-facing protocol. See the [background-task runtime RFC](../../docs/rfc/implemented/architecture/2026-06-20-generic-long-running-tool-runtime.md).
+The shared home for background-task ids, owner isolation, reads, cancellation, waiting, and completion notices. Bash, subagents, and future long-running tools use one model-facing protocol. See the [background-task runtime Agent Note](../../.agents/notes/implemented/architecture/2026-06-20-generic-long-running-tool-runtime.md).
 
 | Package | ctx key | Role |
 |---|---|---|

packages/tasks/tasks/README.md

@@ -20,12 +20,16 @@ Tasks belong to their owner and backend, not the producer tool fiber, so produce
 
 Service disposal closes listeners, cancels all live tasks, awaits their records, and detaches effects from surviving owner scopes. If teardown cancellation throws, the service force-fails the record and warns that work may be orphaned instead of deadlocking. A cancellation that returns but never settles `done` remains indistinguishable from a slow stop and can stall teardown.
 
-See the [task type catalog](../../../docs/core-data-structures/tasks.md) and [runtime RFC](../../../docs/rfc/implemented/architecture/2026-06-20-generic-long-running-tool-runtime.md).
+See the [task type catalog](../../../docs/core-data-structures/tasks.md) and [runtime Agent Note](../../../.agents/notes/implemented/architecture/2026-06-20-generic-long-running-tool-runtime.md).
 
 ## Model Experience
 
 Indirectly, through producer plugins and [`dsh-tool-tasks`](../tool-tasks/README.md), which render task ids, output, status, cancellation, and completion notices.
 
+#### KV Cache effect
+
+No direct invalidation; the named consumer owns any request-prefix changes.
+
 ## Known Limitations and Deferred Work
 
 - **Tasks are process-local** — durable or cross-restart execution needs a separate lifecycle.

packages/tasks/tool-tasks/README.md

@@ -27,27 +27,51 @@ A default above the cap fails at load.
 
 ### System prompt
 
-**What the model sees**: Every request in this plugin's registration scope contains this guidance. Agent-scoped tool filtering may hide the tools without removing the independently registered prompt section.
+#### What the model sees
 
-**Token effect**: Small fixed input cost per request while active.
+Every request in this plugin's registration scope contains this guidance. Agent-scoped tool filtering may hide the tools without removing the independently registered prompt section.
 
-#### Background-task guidance
+##### Background-task guidance
 
 ```markdown
 Track every background task id you start. You are notified in-session when a task finishes — do not busy-poll or sleep on one; keep working on independent steps and do not duplicate a running task's work. Before giving a final answer, collect every still-relevant task with task_output (set wait: true only when you are genuinely blocked on it), and task_kill tasks that stopped mattering.
 ```
 
+#### Token effect
+
+Small fixed input cost per request while active.
+
+#### KV Cache effect
+
+Prefix-stable while the plugin scope and guidance text are unchanged. Activation or disposal may invalidate reuse from this prompt section.
+
 ### Tool schemas
 
-**What the model sees**: The generated [`task_output`, `task_list`, and `task_kill` schemas](../../../docs/tool-catalog.md#deepseek-aidsh-tool-tasks) while this surface is visible.
+#### What the model sees
 
-**Token effect**: Fixed schema cost on each request where the tools are visible.
+The generated [`task_output`, `task_list`, and `task_kill` schemas](../../../docs/tool-catalog.md#deepseek-aidsh-tool-tasks) while this surface is visible.
+
+#### Token effect
+
+Fixed schema cost on each request where the tools are visible.
+
+#### KV Cache effect
+
+Prefix-stable while tool definitions and visibility are unchanged. Registration lifecycle or scoped restrictions may invalidate reuse from the first changed schema token.
 
 ### Results and notices
 
-**What the model sees**: Reads return output or `(no new output)` followed by `[status: <status>]` and optional detail. An empty list returns `(no background tasks)`. Kill returns `requested cancellation of task <id>` or the existing terminal status. Unreported owned completion uses the notice above.
+#### What the model sees
 
-**Token effect**: Results and notices remain in parent history until compaction. Stream reads do not repeat consumed output.
+Reads return output or `(no new output)` followed by `[status: <status>]` and optional detail. An empty list returns `(no background tasks)`. Kill returns `requested cancellation of task <id>` or the existing terminal status. Unreported owned completion uses the notice above.
+
+#### Token effect
+
+Results and notices remain in parent history until compaction. Stream reads do not repeat consumed output.
+
+#### KV Cache effect
+
+Append-only; newly visible content follows the reusable request prefix and does not invalidate existing KV-cache entries.
 
 ## Known Limitations and Deferred Work