docs(plan): update engine v2 architecture to match verified reality#2801
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…ality The plan doc claimed several items as missing/pending that are already implemented. Update to match ground truth so future readers don't redo the verification pass. Changes: - Compaction (§4.3): marked DONE, pointer to orchestrator/default.py:240-310 - Tool reliability (§4.9): tracker exists; integration tracked in #2800 PR-B - Routines/Jobs (§6.7): routine_to_mission_alias already translates routine_* calls; create_job aliasing tracked in #2800 PR-C - Two-phase commit (§6.7): marked IMPLEMENTED via unified gate (policy.rs:126-169 + structured.rs:139-171); simulate/preview intentionally not added at policy layer - Acceptance testing (§6.7): pointer to with_engine_v2 harness; coverage expansion tracked in #2800 PR-D - Phase 7: split into 7a (engine-side, DONE) and 7b (host cleanup, blocked on default flip) - Status header + Implementation Progress table: updated to match current state; default-flip work consolidated under issue #2800 No code changes. Refs: #2800 Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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This pull request updates the Engine v2 architecture documentation to reflect the current implementation status, specifically noting that Phase 7 engine-side cleanup is complete and Phase 8 infrastructure integration is underway. Key technical updates include documenting the Python-based compaction logic, the implementation of the ReliabilityTracker for tool performance, and the unified gate mechanism for two-phase commits. The review feedback identifies several technical inaccuracies in the documentation regarding token estimation ownership, non-existent file references, the current state of the tool denylist, and the specific provenance triggers for effect approvals.
| - Stores a snapshot in state history for audit | ||
| - Full prior trajectory stays searchable via workspace-backed retrieval; raw history is not replayed into the attention window | ||
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| Rust side provides token estimation, retrieval helpers, and final transcript commit points; the orchestrator owns the mutable working transcript it sends to the LLM. |
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The document states that the Rust side provides token estimation, but the implementation in orchestrator/default.py (lines 226-238) uses a Python-side heuristic (estimate_context_tokens) instead of a host function. The description should be updated to reflect that the orchestrator performs this estimation.
| Rust side provides token estimation, retrieval helpers, and final transcript commit points; the orchestrator owns the mutable working transcript it sends to the LLM. | |
| Rust side provides retrieval helpers and final transcript commit points; the orchestrator owns the mutable working transcript it sends to the LLM and performs token estimation via a heuristic. |
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Fixed in 1b9c47c — moved token estimation ownership to the Python orchestrator and left Rust with retrieval helpers + final transcript commit points only.
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| Rust side provides token estimation, retrieval helpers, and final transcript commit points; the orchestrator owns the mutable working transcript it sends to the LLM. | ||
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| Note: the crate-structure block above mentions `executor/compaction.rs` — that file was never created. Compaction lives entirely in Python; the Rust side only exposes the primitives the Python orchestrator calls. |
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The note mentions that the crate-structure block above includes executor/compaction.rs, but that file is not present in the structure listed in lines 97-103. This reference should be removed or updated to avoid confusion.
| Note: the crate-structure block above mentions `executor/compaction.rs` — that file was never created. Compaction lives entirely in Python; the Rust side only exposes the primitives the Python orchestrator calls. | |
| Note: Compaction lives entirely in Python; the Rust side only exposes the primitives the Python orchestrator calls. |
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Fixed in 1b9c47c — dropped the stale cross-reference. Now just notes that compaction lives entirely in Python and the Rust side exposes the primitives the orchestrator calls.
| - Routines still work via `/routine` slash commands (fall through to v1) | ||
| - Engine v2 Mission APIs exist and are wired through the bridge; remaining work is migration/UX convergence rather than greenfield implementation | ||
| - `routine_create` / `routine_update` / `routine_list` / etc. are translated to mission_* dispatches via `routine_to_mission_alias()` in `src/bridge/effect_adapter.rs` before the v1-denylist check fires. The LLM-facing routine tools go through the mission manager in v2, not the v1 routine engine. | ||
| - Tracked in issue #2800 (PR-C): extend the alias to cover `create_job` / `cancel_job` as well. Only `build_software` remains hard-denylisted as v1-specific infra. |
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The statement "Only build_software remains hard-denylisted" is slightly premature as it describes the desired state after PR-C is completed. Currently, create_job and cancel_job are also still hard-denylisted in src/bridge/effect_adapter.rs:2275-2283.
| - Tracked in issue #2800 (PR-C): extend the alias to cover `create_job` / `cancel_job` as well. Only `build_software` remains hard-denylisted as v1-specific infra. | |
| - Tracked in issue #2800 (PR-C): extend the alias to cover create_job / cancel_job as well, after which only build_software will remain hard-denylisted as v1-specific infra. |
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Fixed in 1b9c47c — reworded to "...after which only build_software will remain hard-denylisted" so it's clearly describing the post-PR-C state, not current staging.
| 1. Simulate → preview | ||
| 2. Approve → user/policy | ||
| 3. Execute → actual effect | ||
| - `PolicyEngine::evaluate_with_provenance` injects `RequireApproval` for `WriteExternal` and `Financial` effects when triggered by `LlmGenerated` or `ToolOutput` provenance (`crates/ironclaw_engine/src/capability/policy.rs:126-169`). |
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The description of provenance-based approval is slightly inaccurate. According to the implementation in policy.rs:153-161, ToolOutput provenance currently only triggers RequireApproval for Financial effects, not WriteExternal effects.
| - `PolicyEngine::evaluate_with_provenance` injects `RequireApproval` for `WriteExternal` and `Financial` effects when triggered by `LlmGenerated` or `ToolOutput` provenance (`crates/ironclaw_engine/src/capability/policy.rs:126-169`). | |
| - PolicyEngine::evaluate_with_provenance injects RequireApproval for Financial effects (via LlmGenerated or ToolOutput provenance) and WriteExternal effects (via LlmGenerated provenance) (crates/ironclaw_engine/src/capability/policy.rs:126-169). |
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Fixed in 1b9c47c — rewrote to "injects RequireApproval for Financial effects (via LlmGenerated or ToolOutput provenance) and WriteExternal effects (via LlmGenerated provenance)" to match policy.rs:126-169 exactly (ToolOutput only taints Financial, not WriteExternal).
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Pull request overview
Updates the engine v2 architecture plan document to reflect the current, verified implementation state and re-align status/progress sections with shipped code (tracked under issue #2800).
Changes:
- Updates status header + implementation progress table to reflect completed phases (incl. Phase 6 + 7a) and current Phase 8 focus.
- Rewrites plan sections (compaction, tool reliability, routines/jobs, two-phase commit, acceptance testing, cleanup/migration) with references to concrete code locations.
- Adds clarifications where prior plan text described aspirational or outdated architecture.
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| - `SkillSelector` / `LoadedSkill` → engine `Capability` (knowledge) | ||
| - `HookPipeline` → engine `Capability` (policies) | ||
| - `ApprovalRequirement` / `ApprovalContext` → engine `CapabilityLease` + `PolicyEngine` | ||
| The `ironclaw_engine` crate contains zero references to `JobState`, `Session`, `Routine`, or v1 delegate types. The engine was built clean from day one on the five primitives (Thread, Step, Capability, MemoryDoc, Project). No migration work is needed inside the crate. |
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“The ironclaw_engine crate contains zero references to ... Session, Routine ...” is not accurate as-written: the terms “Session”/“Routine” appear in crate/module docs (e.g., crates/ironclaw_engine/src/lib.rs and crates/ironclaw_engine/src/types/thread.rs). If the intent is “no runtime dependency on v1 types/modules”, consider rephrasing to that (or narrowing to “no v1 type definitions/usages outside documentation”).
| The `ironclaw_engine` crate contains zero references to `JobState`, `Session`, `Routine`, or v1 delegate types. The engine was built clean from day one on the five primitives (Thread, Step, Capability, MemoryDoc, Project). No migration work is needed inside the crate. | |
| The `ironclaw_engine` crate has no runtime dependency on `JobState`, `Session`, `Routine`, or v1 delegate types; any remaining mentions are limited to documentation/comments. The engine was built clean from day one on the five primitives (Thread, Step, Capability, MemoryDoc, Project). No migration work is needed inside the crate. |
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Fixed in 1b9c47c — rephrased to "no runtime dependency on JobState, Session, Routine, or v1 delegate types; any remaining mentions are limited to documentation/comments". Agreed the prior "zero references" phrasing was too literal given the docs/comment mentions in lib.rs and types/thread.rs.
| Rust should provide token estimates, retrieval helpers, checkpoints, and final transcript commit points. The compaction policy, timing, and prompt should live in the Python RLM loop, and the orchestrator should own the mutable working transcript it sends to the LLM. | ||
| Compaction is orchestrator-owned, in Python. See `crates/ironclaw_engine/orchestrator/default.py:240-310`: | ||
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| - Triggers when token count exceeds 85% of the model limit |
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Compaction trigger is described as fixed at 85% of model limit, but compact_if_needed uses compaction_threshold from config (default 0.85). Consider wording this as “defaults to 85% (configurable via compaction_threshold)” to match the implementation.
| - Triggers when token count exceeds 85% of the model limit | |
| - Triggers when token count exceeds the configured `compaction_threshold` of the model limit (defaults to 85%) |
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Fixed in 1b9c47c — rebuilt the bullet as "Triggers when token count exceeds the configured compaction_threshold of the model limit (defaults to 85%)" so it matches compact_if_needed's config read.
| ### 4.9 Tool reliability learning | ||
| Track per-action EMA metrics (success rate, latency, failure patterns). Current remaining question: whether to inject them into context by default or only surface them through targeted retrieval/debugging. | ||
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| `ReliabilityTracker` (`crates/ironclaw_engine/src/reliability.rs`) records EMA-smoothed success rate and latency per action. Tracked in issue #2800 (PR-B): writes from `EffectBridgeAdapter` after every dispatch, reads from `build_step_context` to append a "recently unreliable actions" section to the system prompt when `call_count ≥ 10` and `success_rate < 0.7` (cap 5 entries, kill switch `ENGINE_V2_RELIABILITY_HINTS`). |
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This paragraph includes detailed behavior (writing from EffectBridgeAdapter, reading from build_step_context, thresholds, and kill switch ENGINE_V2_RELIABILITY_HINTS) that does not appear to exist in the codebase yet (e.g., no ENGINE_V2_RELIABILITY_HINTS usage and no record_success/record_failure calls from the bridge). To keep this plan “verified reality”, either remove the unimplemented details or clearly label them as proposed work for PR-B.
| `ReliabilityTracker` (`crates/ironclaw_engine/src/reliability.rs`) records EMA-smoothed success rate and latency per action. Tracked in issue #2800 (PR-B): writes from `EffectBridgeAdapter` after every dispatch, reads from `build_step_context` to append a "recently unreliable actions" section to the system prompt when `call_count ≥ 10` and `success_rate < 0.7` (cap 5 entries, kill switch `ENGINE_V2_RELIABILITY_HINTS`). | |
| `ReliabilityTracker` (`crates/ironclaw_engine/src/reliability.rs`) records EMA-smoothed success rate and latency per action. Proposed follow-up work tracked in issue #2800 (PR-B): wire `EffectBridgeAdapter` to record outcomes after dispatch, have `build_step_context` optionally surface a "recently unreliable actions" prompt section, and finalize any thresholds, entry caps, and feature-flag/kill-switch behavior (including a possible `ENGINE_V2_RELIABILITY_HINTS` control) once implemented. |
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Fixed in 1b9c47c — relabelled the paragraph as proposed PR-B follow-up work. The threshold/cap/kill-switch details are now described as design proposals to be finalized when EffectBridgeAdapter write-backs and build_step_context reads actually land.
Apply accuracy fixes from PR #2801 review: - Compaction threshold: describe as configurable via `compaction_threshold` (defaults to 85%), matching `compact_if_needed` in the Python orchestrator rather than claiming a fixed 85%. - Token estimation: move ownership to the Python orchestrator (which runs the chars/token heuristic); Rust no longer claims to own this. - Compaction cross-reference: drop the stale "crate-structure block above includes executor/compaction.rs" note — compaction lives entirely in Python. - Reliability injection details (`ENGINE_V2_RELIABILITY_HINTS` kill switch, `EffectBridgeAdapter` write-backs, `build_step_context` reads) are labelled as proposed PR-B follow-up work rather than described as verified reality. - Denylist phrasing: make it clear that `build_software` remains the only hard-denylisted v1 tool *after* PR-C lands, not before. - Provenance rules: document accurately that `ToolOutput` provenance only injects `RequireApproval` on `Financial` effects; `WriteExternal` taint comes only from `LlmGenerated`, per policy.rs:126-169. - Engine-side cleanup: acknowledge that `Session` / `Routine` identifiers still appear in engine docs/comments; the invariant is no runtime dependency, not zero string occurrences. No code changes. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Paranoid Architect Review — Approve with Fixes2 Medium findings. The verification pass is mostly accurate — claims about implemented functionality check out against the codebase. Two issues remain. Medium
Fixes needed
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| ### 4.3 Compaction (from RLM) — IMPLEMENTED | ||
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| Rust should provide token estimates, retrieval helpers, checkpoints, and final transcript commit points. The compaction policy, timing, and prompt should live in the Python RLM loop, and the orchestrator should own the mutable working transcript it sends to the LLM. | ||
| Compaction is orchestrator-owned, in Python. See `crates/ironclaw_engine/orchestrator/default.py:240-310`: |
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Medium: Wrong line range. compact_if_needed() spans lines 206-276 in orchestrator/default.py, not 240-310. The cited range starts in the middle of the function (at the history.append() block) and overflows into the unrelated score_skill() function which starts at line 282.
Rewrites sections of
docs/plans/2026-03-20-engine-v2-architecture.mdthat had drifted from the code. No code changes.What this fixes
A verification pass against the actual implementation showed that several items the plan marked as "pending" or "not yet implemented" were in fact shipped. Future readers relying on the plan would redo the same verification work.
Sections rewritten
orchestrator/default.py:240-310ReliabilityTrackerexists; integration tracked #2800 PR-Broutine_*already aliased to mission_*;create_jobaliasing in #2800 PR-Cpolicy.rs:126-169+structured.rs:139-171)with_engine_v2harness; coverage list moved to #2800 PR-DTracking
Part of umbrella issue #2800 (engine v2 default flip).
Test plan
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