Merge remote-tracking branch 'origin/master' into session-query-trace

# Conflicts:
#	docs/cordis-catalog/services.md
#	packages/core/session/README.md
#	packages/support/invariants/src/index.ts
#	packages/support/invariants/tests/invariants.spec.ts

docs/rfc/proposed/feature/2026-07-07-claude-code-and-codex-subagent-backends.md

@@ -4,7 +4,7 @@ Status: proposed
 
 ## Problem
 
-The subagent seam ([the seam RFC](../../implemented/feature/2026-06-21-subagent-capability-seam.md)) hosts multiple named providers on `ctx.subagents`, and the ACP backend ([the ACP backend RFC](../../implemented/feature/2026-06-22-acp-subagent-backend.md)) proved the seam generalizes across a process boundary; its Future-providers section explicitly named the Codex app-server and the Claude Code Agent SDK as mechanically similar siblings. Those two are the engines actually worth delegating to today: a harness turn should be able to hand a self-contained task to a real Claude Code or a real Codex — a separate product with its own model, tools, and sandbox — and get back one final answer, without the parent deployment leaking its secrets into the child or the child's behavior silently depending on whatever `~/.claude` / `~/.codex` state exists on the host machine.
+Add isolated subagent providers for Claude Code and Codex. The existing [named-provider seam](../../implemented/feature/2026-06-21-subagent-capability-seam.md) and [ACP backend](../../implemented/feature/2026-06-22-acp-subagent-backend.md) establish the process-boundary shape. A harness turn should be able to delegate a self-contained task to either product and receive its final answer without exposing parent secrets or inheriting host configuration from `~/.claude` or `~/.codex`.
 
 ## Proposal
 
@@ -14,7 +14,7 @@ Two sibling provider packages, structural variants of the ACP backend, plus one
 - `@deepseek-ai/dsh-subagent-codex` — spawns `codex app-server` and drives one thread/turn over its JSON-RPC-over-stdio protocol with a hand-rolled newline-JSON client (~200–300 lines) in the package.
 - `@deepseek-ai/dsh-subagent-process` — a pure library (the `subagent-inprocess` precedent) extracting what `dsh-subagent-acp` already carries and both new backends need: the credential env scrub (`SENSITIVE_ENV_PATTERN`/`buildChildEnv`), the EOF → SIGTERM → SIGKILL dispose ladder, and new isolated-config-dir helpers (`mkdtemp` create, best-effort remove). The ACP backend migrates onto it; `bash-local`'s sibling copy is left alone to bound the change.
 
-Both providers copy the ACP backend's seam posture verbatim: fresh child per `start`, exactly one prompt round-trip, capabilities all `false`, `inheritsParentContext: false`, `request.parent`/`request.agentOptions` ignored, `id = AgentId(randomUUID())`, `result` never rejects — child-level failure flattens to a stop reason and the original error goes to `ctx.logger` via an `onError` spec callback. Model exposure is zero new code: `dsh-tool-subagent` is loaded once per provider with a distinct `toolName` (`subagent_claude_code`, `subagent_codex`). No new session events are needed — the only model-visible artifact is the tool result, so reconstructability holds exactly as it did for ACP. To be explicit about the boundary: the session log reconstructs the model-visible transcript, not workspace mutation history — a child granted write access mutates files as an ambient side effect outside the log, exactly as the bash tools and the ACP backend already do; replay reproduces requests, not the disk.
+Both providers follow the ACP backend contract: a fresh child per `start`, one prompt round-trip, no inherited parent context or advertised optional capabilities, ignored `request.parent` and `request.agentOptions`, and a random branded agent id. `result` never rejects; child failures map to stop reasons while the original error reaches the logger. Each mounts `dsh-tool-subagent` under a distinct tool name. The tool result is the only new model-visible artifact, so no new session event is required; workspace mutations remain ambient side effects outside transcript replay.
 
 ## Verified interface facts (pinned versions)
 
@@ -31,11 +31,11 @@ Both integration surfaces were verified against pinned implementations before th
 
 ## Isolation and credentials
 
-Deployments authenticate with API keys only, and the child must not see the host user's Claude Code / Codex configuration: behavior has to be a function of `cordis.yml` alone. Each run gets a fresh `mkdtemp` config dir — `CLAUDE_CONFIG_DIR` for Claude Code (paired with an explicit `settingSources: []`), `CODEX_HOME` for Codex — removed best-effort on dispose; a config field can pin a persistent dir instead. The child env reuses the ACP backend's `buildChildEnv` semantics verbatim via the extraction: the ambient env is forwarded MINUS credential-shaped vars (`/KEY|SECRET|TOKEN/i`), with `config.env` layered on top — so `PATH`, `HOME`, `TMPDIR`, locale, and proxy vars survive and the CLIs run normally, while only credential-shaped ambient vars are scrubbed (`ANTHROPIC_API_KEY` enters explicitly through `config.env` for Claude Code), and the Codex key travels via the `account/login/start` RPC into the isolated `CODEX_HOME` rather than a hand-written `auth.json`.
+Authentication is API-key-only. Each run uses a fresh config directory (`CLAUDE_CONFIG_DIR` with `settingSources: []`, or `CODEX_HOME`) that is removed best-effort on dispose; config may instead select a persistent directory. The shared child-env helper forwards ordinary values such as `PATH`, `HOME`, `TMPDIR`, locale, and proxy settings, removes credential-shaped names, and overlays explicit `config.env`. Claude Code receives its API key through that overlay, while Codex receives it through `account/login/start` rather than a hand-written auth file.
 
 ## Permission and approval policy
 
-Instead of collapsing to ACP's single `permission: allow|reject` knob, each backend exposes its engine's native vocabulary as config, with conservative defaults: Claude Code gets `permissionMode` (default `default`) plus `permission: allow|reject` (default `reject`) as the `canUseTool` auto-answer for whatever falls through; Codex gets `sandboxMode` (default `read-only`) and `approvalPolicy` (default `never`) plus the same `permission` fallback for approval requests that still arrive. Defaults are deliberately do-no-harm (the out-of-box child cannot write files); examples demonstrate opening up (`acceptEdits` / `workspace-write`). The mechanical rule: EVERY server-initiated request is settled programmatically and promptly — the enumerated approval/user-input/elicitation requests by the configured policy, an unknown request method with a JSON-RPC method-not-found error response (never left pending), unknown notifications consumed — so no child request can wedge a turn waiting on an answer that will never come. Prompts never reach a human in this cut, matching ACP.
+Each backend exposes its engine's native policy vocabulary. Claude Code defaults to `permissionMode: default` with `permission: reject`; Codex defaults to `sandboxMode: read-only`, `approvalPolicy: never`, and the same rejected fallback. Examples opt into `acceptEdits` or `workspace-write`. Known approval, user-input, and elicitation requests receive the configured answer; unknown methods receive method-not-found and unknown notifications are consumed. No prompt reaches a human, and no child can wait indefinitely for unavailable input.
 
 ## StopReason mapping
 
@@ -45,11 +45,11 @@ Liveness posture, stated explicitly: teardown timing is config, turn duration is
 
 ## Testing
 
-Named at every tier per the root AGENTS.md rule, and de-risked up front:
+Coverage is required at each applicable tier:
 
-- **Keyless unit/integration**, mirroring the ACP spec list per backend (round-trip and output accumulation, every stop mapping, both cancel paths, already-aborted, permission auto-answer under both policies, unknown-message tolerance, bad-command spawn failure, HMR provider cleanup, export shape, isolation assertions on child env and temp-dir removal; Codex adds the auth-precheck failure path). Claude Code's harness is a scripted fake `claude` executable behind `pathToClaudeCodeExecutable` driven by the REAL SDK — a spike already passed end-to-end keyless in 24ms (the fake CLI answers one `control_request/initialize` and speaks plain stream-json, ~40 lines). Codex's harness is a scripted mock app-server subprocess speaking the verified wire protocol, the `mock-acp-server.ts` shape.
-- **With-key e2e** per backend: the real engine does real file work verified on disk, under a pinned opened-up config so acceptance and the do-no-harm defaults don't collide — `permissionMode: 'acceptEdits'` for Claude Code, `sandboxMode: 'workspace-write'` + `approvalPolicy: 'never'` for Codex; self-skips report exactly what is missing (binary vs key). CI has no secrets, so these run locally per the with-key policy.
-- **Snapshot**: deferred as `TODO(claude-code-subagent-replay)` / `TODO(codex-subagent-replay)` — the same distinct replay shape the ACP backend deferred ([the per-session replay RFC](../../implemented/testing/2026-06-22-subagent-snapshot-replay.md)); the keyless suites carry deterministic coverage meanwhile.
+- **Keyless unit/integration:** drive a fake Claude CLI through the real SDK and a scripted Codex app-server through the real wire client. At per-file 100% coverage, exercise round trips, every stop mapping, both cancellation paths and pre-abort, permission policies, unknown messages, spawn failure, reload cleanup, export shape, scrubbed environments, temporary-directory removal, and Codex auth precheck failure.
+- **With-key e2e:** each real engine performs file work under `acceptEdits` or `workspace-write`; skips name the missing binary or key and assert no child process remains.
+- **Snapshot:** deferred as `TODO(claude-code-subagent-replay)` and `TODO(codex-subagent-replay)` pending the process-specific replay shape described by the [subagent replay RFC](../../implemented/testing/2026-06-22-subagent-snapshot-replay.md).
 
 ## Alternatives considered
 

docs/rfc/proposed/feature/2026-07-08-interactive-side-sessions.md

@@ -4,45 +4,36 @@ Status: proposed
 
 ## Problem
 
-A user deep in a live session often wants to fork the conversation — ask "why did we structure it this way", explore an alternative, get an explanation — without polluting the main context and without abandoning the surface they are in. The harness has every primitive this needs and no product face for it: [the session-store fork API](../../implemented/feature/2026-06-30-session-store-fork-api.md) produces a `Session` with no attached agent and no way for a client to reach it, and [the fork subagent](../../implemented/feature/2026-06-21-subagent-capability-seam.md) seeds a child with the parent's prefix but runs it as a model-driven task whose whole transcript collapses into one tool result — neither yields a forked conversation the USER can talk to.
-
-The return path is missing entirely: nothing carries a conclusion from one branch back into another. Whatever the user learns in an exploration branch is copy-pasted by hand or lost, with no provenance and no replayable record.
-
-Terminal-first competitors ship half of each: single-shot side questions with inherited context, and user-switched branch copies that force a client restart. None ship the return verb. A harness that owns its session store and context assembly can do both cheaply — and can do so without breaking the provider prefix cache, which third-party wrappers structurally cannot.
+A user may want to explore a question from a live session without changing its main context. Existing primitives do not expose that product shape: [session-store fork](../../implemented/feature/2026-06-30-session-store-fork-api.md) creates an unattached session, while [fork subagents](../../implemented/feature/2026-06-21-subagent-capability-seam.md) are model-driven tasks whose transcript collapses into one tool result. Neither gives the user a separate conversation, and neither records a conclusion back into the parent with provenance.
 
 ## Proposal
 
-A **side session** is an ordinary live session forked from a source session at its last completed turn, attached to its own agent, framed as a read-only advisor, with one new verb — **merge-back** — that hands a condensed note to the parent.
+A **side session** is an ordinary live session forked at the source's last completed turn, attached to its own agent, framed as a read-only advisor, and able to **merge back** one condensed note.
 
-- **Fork + attach composes existing primitives.** The child is created via `ctx.agents.create({ seed, meta })` with the parent's balanced completed-turn prefix (the same slice the fork subagent takes) and `parentSession`/`seedLength` lineage stamped in `meta`. No new core service and no session-store change, for the same reasons [the fork API RFC](../../implemented/feature/2026-06-30-session-store-fork-api.md) rejected a standalone fork service.
-- **Advisor framing rides the log, not the system prompt.** The rules ("you are a read-only side advisor; explain, do not mutate; refuse task continuation") are `inject()`ed as a `context/message` with source `{ kind: 'plugin', plugin: 'sidechat' }` immediately after creation. The child's system prompt stays byte-identical to the parent's, so the provider's prefix cache covers the inherited history.
-- **Merge-back is one condense turn plus one injection.** The child is prompted for a bounded handback note (a hard length cap), which is then `inject()`ed into the PARENT as a `context/message` with the same plugin source. The parent's next request sees it at its chronological position; replay and [reconstructability](../../implemented/architecture/2026-07-05-reconstructable-requests.md) hold by construction; no new event type enters [the session vocabulary](../../../core-data-structures/session.md).
-- **The surface binding is deliberately unspecified.** How a user invokes the fork and the merge, and how a handback note is presented, are client concerns; while the harness speaks through protocols whose UI it does not control, this RFC pins only the surface-agnostic mechanics above and leaves presentation to the first surface the project owns.
+- **Fork and attach:** create the child with the parent's balanced completed-turn prefix and stamp `parentSession` and `seedLength` in its metadata. This composes `ctx.agents.create({ seed, meta })`; it adds no core service or session-store method.
+- **Advisor framing:** inject one plugin-sourced `context/message` after creation that tells the child to explain without mutating or continuing the task. Keeping the system prompt byte-identical preserves the provider prefix cache over inherited history.
+- **Merge-back:** ask the child for a length-capped handback, then inject one plugin-sourced `context/message` into the parent. The next parent request sees it at its logged position, preserving replay and [request reconstructability](../../implemented/architecture/2026-07-05-reconstructable-requests.md) without a new session event.
+- **Presentation:** invocation, session switching, and handback rendering belong to the first client-owned surface. This RFC specifies only the surface-independent mechanics.
 
-Scope also excludes: rewind productization (mechanically the same fork-to-an-earlier-boundary, an entirely different product question), session tree views, a model-facing side-session tool, and `forkName`/`mergedInto` metadata.
-
-## Prototype
-
-A spike (branch `spike/side-sessions-b`) validates the mechanics against the live adapter: a fork that leaves the source log untouched, a child seeded with the full inherited prefix, a multi-turn advisor exchange that demonstrably uses parent history, and a merge-back the parent's next turn quotes correctly.
+Rewind productization, session-tree views, a model-facing side-session tool, and `forkName`/`mergedInto` metadata are out of scope. A live-adapter spike validated source-log isolation, inherited context, a multi-turn child exchange, and merge-back visibility in the parent's next turn.
 
 ## Alternatives considered
 
-- **Carry side conversations through the subagent seam.** Rejected: a subagent child is a model-driven run — the parent's model spawns it, drives it, and consumes its result as a tool result. A side session is user-driven, needs its own client-visible session and lifecycle, and must outlive any single parent turn.
-- **Persona via `system-prompt/assemble` section filtering.** Rejected as the default path: any system-prompt byte change invalidates the provider prefix cache from token 0, forfeiting the cheap fork that makes side sessions attractive on long histories. The filter seam remains available for deployments that prefer hard prompt separation over cache reuse.
-- **A dedicated `sidechat/*` event family for the handback.** Deferred: `context/message` with a mandatory plugin source already satisfies durability, provenance, and replay. A first-class event earns its catalog, persistence, and snapshot costs only if a UI needs to render handbacks as dedicated cards.
-- **Binding the proposal to a protocol surface now.** Rejected in review: the harness currently speaks through client-owned UIs it does not control, so any presentation contract written today would be speculative. The RFC pins the surface-agnostic mechanics and defers presentation to the first surface the project owns.
-- **Surface-level mirroring of the handback.** Rejected in review: a visible record emitted outside the log vanishes on replay while the model still sees it. Whatever surface eventually renders the handback must derive its presentation from the durable `context/message`, so live and replayed views come from the same event.
+- **Use the subagent seam:** rejected because side sessions are user-driven, client-visible, and may outlive a parent turn; subagents are model-driven runs returning one tool result.
+- **Change the child system prompt:** rejected by default because any byte change invalidates the prefix cache from token zero. Deployments may still prefer that stronger separation.
+- **Add `sidechat/*` events:** deferred because a sourced `context/message` already provides durability, provenance, and replay. A dedicated event is justified only by a surface that needs distinct rendering.
+- **Bind a protocol surface now:** rejected because current UIs are client-owned. Live presentation must eventually derive from the durable message so replay renders the same record.
 
 ## Acceptance criteria
 
-- Forking a live session yields a child agent seeded with the source's balanced completed-turn prefix, with `parentSession` and `seedLength` in its header and a system prompt byte-identical to the parent's; the source log is untouched by the fork.
-- The advisor framing is exactly one plugin-sourced `context/message` at the head of the child's appended history — never a system-prompt change.
-- Merge-back appends exactly one length-capped `context/message` to the parent with source `plugin: sidechat`; the parent's next request sees it, and replay reproduces it at the same position.
-- Parent and child run concurrently without cross-talk between their logs or streams.
-- Coverage: unit tests for the fork/attach and merge-back mechanics; surface-level snapshot coverage lands with whichever surface first binds the feature.
+- Forking leaves the source untouched and creates a child with the balanced completed-turn prefix, `parentSession`, `seedLength`, and a byte-identical system prompt.
+- Advisor framing adds exactly one plugin-sourced `context/message` at the head of the child's appended history, rather than changing its system prompt.
+- Merge-back adds exactly one length-capped `context/message` with source `plugin: sidechat`; the next parent request and replay see it at the same position.
+- Parent and child run concurrently without log or stream cross-talk.
+- Unit tests cover fork/attach and merge-back; snapshot coverage lands with the first bound surface.
 
 ## Risks
 
-- **Read-only is advisory in v1.** The rules are injected context, not enforcement; a determined prompt can still drive mutating tools. The hard gate is a `tools/pre-execute` deny via [the interception seams](../../implemented/feature/2026-06-30-interception-seams.md), and the RFC's advisor framing is written so that gate can be added without changing the mechanics.
-- **A compacted source forks its compacted view.** The child inherits the summary, not the original turns; whichever surface binds the feature should disclose this once [compaction](../../implemented/feature/2026-06-18-compaction-capability-seam.md) ships in this path.
-- **Handback notes spend parent tokens.** The length cap and one-note-per-merge bound the cost, but a user who merges repeatedly accumulates notes; a future consolidation pass belongs to the compaction work, not here.
+- Read-only behavior is advisory until a `tools/pre-execute` deny gate enforces it; [the interception seam](../../implemented/feature/2026-06-30-interception-seams.md) can add that gate without changing these mechanics.
+- A compacted source forks its compacted view, so a bound surface should disclose that the child inherits summaries rather than replaced turns.
+- Repeated handbacks consume parent context. The per-merge length cap bounds each note; later consolidation belongs to compaction.