<!-- task=m-iop-hot-path-one-shot-execution/14+13_anthropic_gate plan=3 tag=REVIEW_API milestone-task=terminal-control,anthropic-gate -->

# Code Review Reference - REVIEW_API

> **[IMPLEMENTING AGENT — READ FIRST] Filling in this file is the mandatory final step of implementation.**
> The task is NOT complete until every implementation-owned section below is filled in.
> Complete the `Implementation Checklist`; the final checklist item is mandatory before saving.
> Fill implementation-owned sections, then stop with active files in place and report ready for review.
> If implementation is blocked, record the exact blocker, attempted commands/output, and resume condition only in implementation-owned evidence fields.
> Do not ask the user directly, present choices, call user-input tools, create control-plane stop files, or classify the next state.
> Finalization (`Code Review Result`, log rename, `complete.log`, archive moves, `Review-Only Checklist`) is review-agent-only, even after compaction/resume.
> Follow the ownership table at the bottom of this file for which sections you own.

## Overview

date=2026-08-03
task=m-iop-hot-path-one-shot-execution/14+13_anthropic_gate, plan=3, tag=REVIEW_API

## Archive Evidence Snapshot

- `plan_cloud_G09_2.log` contains the completed identity, token-budget, and production live-stage repair whose decoder baseline this follow-up preserves.
- `code_review_cloud_G10_2.log` records `FAIL` with one Required finding in `hot_path_stage_stream.go`: an Anthropic `tool_use` with `input: {}` and no argument delta produces no normalized tool fragment. Reviewer reruns of the targeted race suite, common race suite, formatting check, and `git diff --check` passed; a focused decoder reproducer failed with `empty-input tool_use was dropped: events=[]`.
- The follow-up changes only empty-input tool preservation and its handler-level regression; evidence integrity is trusted.

## For the Review Agent

> **[REVIEW AGENT ONLY]** The finalization steps below are review-agent only. Implementing agents must not execute this section.

Compare implementation of each item against source files and verify that output in `Verification Results` matches code.
Review completion means the following steps are finished:

1. Append verdict and `review_rework_count` / `evidence_integrity_failure` routing signals.
2. Archive `CODE_REVIEW-cloud-G05.md` → `code_review_cloud_G05_3.log` and `PLAN-cloud-G04.md` → `plan_cloud_G04_3.log`.
3. If PASS, write `complete.log` and move active task directory to `agent-task/archive/YYYY/MM/m-iop-hot-path-one-shot-execution/14+13_anthropic_gate/`. If WARN/FAIL, fully write the next filesystem state required by the code-review skill.
4. If PASS, preserve the first-line `milestone-task` metadata in `complete.log` and report it for runtime aggregation. Roadmap state evaluation belongs to `sync-milestone-workstate`.
5. Check applicable `Review-Only Checklist` items at the final `.log` location before reporting.

---

## Implementation Item Completion

| Item | Status |
|---|---|
| API-1 Empty-input Anthropic tool preservation | [x] |

## Implementation Checklist

- [x] [API-1] Preserve exactly one empty Anthropic tool argument object when a live `tool_use` block closes without an input fragment, and add its native handler regression.
- [x] Run the targeted and common race suites plus `git diff --check` exactly as listed in Final Verification.
- [x] Fill implementation-owned sections in `CODE_REVIEW-*-G??.md` with actual implementation notes and verification output.

## Review-Only Checklist

> **[REVIEW AGENT ONLY]** This checklist is used only by the review agent.
> Implementing agents must not modify or check this section.

- [x] Append one verdict of `PASS`, `WARN`, or `FAIL` and verified `review_rework_count`, `evidence_integrity_failure` to `Code Review Result`.
- [x] Verify that verdict, `Dimension Assessment`, and Required/Suggested/Nit classifications match.
- [x] Archive active `CODE_REVIEW-*-G??.md` to `code_review_cloud_G05_3.log`.
- [x] Archive active `PLAN-*-G??.md` to `plan_cloud_G04_3.log`.
- [x] Verify that the Agent-Ops managed block in `.gitignore` unignores `agent-task/**/*.md` and `agent-task/**/*.log` and ignores `agent-roadmap/current.md`.
- [x] If PASS, write `complete.log` based on `agent-ops/skills/common/code-review/templates/complete-log-template.md` and leave no active `.md` files.
- [x] If PASS, move active task directory `agent-task/m-iop-hot-path-one-shot-execution/14+13_anthropic_gate/` to `agent-task/archive/YYYY/MM/m-iop-hot-path-one-shot-execution/14+13_anthropic_gate/` and update this checklist at the final archive path.
- [x] If PASS and task group is `m-iop-hot-path-one-shot-execution`, preserve and report `milestone-task` metadata for runtime aggregation, without modifying roadmap or directly calling `update-roadmap`.
- [x] If PASS for split work, remove empty active parent `agent-task/m-iop-hot-path-one-shot-execution/` or verify it was kept due to remaining siblings/files.
- [ ] If WARN/FAIL, write the next filesystem state matching code-review verdict and do not write `complete.log`.

## Deviations from Plan

None. In addition to updating the live streaming stage decoder, `decodeAnthropicPresetSSE` in `hot_path_dispatch.go` was updated to handle `content_block_stop` consistently for zero-argument tool calls.

## Key Design Decisions

Updated `anthropicMessagesStageDecoder` to track `anthropicStageTool{identity, inputEmitted}` per block index. When `content_block_start` or `input_json_delta` emits non-empty input, `inputEmitted` is set to `true`. When `content_block_stop` is decoded, if `inputEmitted` is `false`, a single `ToolCallFragmentEvent` containing `{}` is emitted for the closed block, and the block state is deleted.

## Reviewer Checkpoints

- Confirm a closed native Anthropic `tool_use` with `input: {}` and no `input_json_delta` yields one normalized/public `{}` argument fragment and one continuation mapping.
- Confirm fragmented non-empty arguments remain unchanged and do not receive a leading or trailing fallback `{}`.
- Confirm tool identity, direct/light classification, Anthropic terminal ordering, and exactly-once terminal ownership remain intact.

## Verification Results

### Targeted Anthropic and outer-turn race tests

Command: `go test -race -count=1 ./apps/edge/internal/openai -run 'TestHotPathAnthropic|TestHotPathOuterTurn|TestHotPathStage|TestAnthropic(ChatBridge|Native)'`

Output:

```text
ok  	iop/apps/edge/internal/openai	2.086s
```

Exit status: `0`

### Common regression race tests

Command: `go test -race -count=1 ./packages/go/streamgate ./packages/go/config ./apps/edge/internal/openai ./apps/edge/internal/service`

Output:

```text
ok  	iop/packages/go/streamgate	2.248s
ok  	iop/packages/go/config	1.776s
ok  	iop/apps/edge/internal/openai	12.880s
ok  	iop/apps/edge/internal/service	7.032s
```

Exit status: `0`

### Diff validation

Command: `git diff --check`

Output:

```text
no stdout/stderr
```

Exit status: `0`

---

> **[IMPLEMENTING AGENT — BEFORE SAVING] Have you filled in every implementation-owned section?**
> If anything is blank, go back and fill it in before saving this file.
> Leave review-agent-only sections unchanged.

## Section Ownership

| Section | Owner | Note |
|---------|-------|------|
| Header comment, Overview, Review Agent Instructions | Fixed at stub creation | Implementing agent must not modify or execute these (archive, complete.log, and task-directory archive move are review-agent only) |
| Archive Evidence Snapshot | Fixed at stub creation from plan when present | Implementing agent uses it as default prior-loop context; read only the specific archive files cited there when more detail is required |
| Implementation Item Completion (item names) | Fixed at stub creation | Implementing agent checks `[ ]` → `[x]` only |
| Implementation Checklist (item text/order) | Fixed at stub creation from plan | Implementing agent checks `[ ]` → `[x]` only |
| Review-Only Checklist | Review agent only | Implementing agent must not modify or check this section |
| Deviations from Plan, Key Design Decisions | Implementing agent | Replace placeholder text with actual content |
| Reviewer Checkpoints | Fixed at stub creation | Pre-filled from plan |
| Verification Results (section headings + commands) | Fixed at stub creation | Implementing agent fills in command output only; command changes require a `Deviations from Plan` entry |
| Code Review Result | Review agent appends | Not included in stub |

## Code Review Result

- Overall Verdict: PASS
- Dimension Assessment:
  - Correctness: Pass — a closed native Anthropic `tool_use` with no input fragment now emits exactly one `{}` fragment, while non-empty fragmented arguments remain unchanged.
  - Completeness: Pass — the live decoder, public Anthropic SSE projection, and continuation mapping satisfy the focused API-1 acceptance path.
  - Test coverage: Pass — the handler-level regression asserts public event order, exactly one `{}` input delta, stable public/provider tool identity, one selector submission, and waiting continuation state.
  - API contract: Pass — zero-argument Anthropic tools remain visible as endpoint-native `tool_use` blocks with an object input and stable correlation.
  - Code quality: Pass — per-block state is removed on close, preventing duplicate fallback fragments without changing unrelated decoder ownership.
  - Implementation deviation: Pass — the collected Anthropic SSE decoder was aligned with the same empty-input close behavior, and the change remains inside the planned protocol boundary.
  - Verification trust: Pass — the reviewer reran both required race commands and `git diff --check`; all exited 0 and matched the implementation evidence.
  - Spec conformance: Pass — the result preserves S10 normalized delta/terminal ordering and S11 native Anthropic tool-use continuation evidence for `terminal-control` and `anthropic-gate`.
- Findings: None.
- Routing Signals:
  - `review_rework_count=2`
  - `evidence_integrity_failure=false`
- Next Step: Write `complete.log`, archive the completed pair and task directory, and report Milestone completion metadata for runtime aggregation.
