Qualify Claude Sonnet 5.5 native structured output

[geeen-jp]

---

AGENT:
Live qualification result: PASS. Minimal runs: 1 exploratory run plus 1 recorded run, one turn each. The recorded run at 2026-09-30 14:43 JST used fork main b1f94099269233b86dc0f93f79a03f1359eb1ff6. This PR changes only tests, so the runtime code is identical.

• Setup:
  • real ACPAgent and LocalConversation, with the default Claude provider command;
  • adapter reported agent_name='@agentclientprotocol/claude-agent-acp', agent_version='0.81.0'; bundled Claude Agent SDK 0.3.280, Claude Code 2.1.280;
  • first-party subscription OAuth seeded into the isolated config, with ANTHROPIC_API_KEY, ANTHROPIC_BASE_URL and ANTHROPIC_AUTH_TOKEN unset;
  • acp_model="claude-sonnet-5-5", acp_permission_policy="read_only", acp_config_options={"effort": "medium"}, and structured_output=StructuredOutputConfig(mode="json_schema", schema=...).
  • The schema: first_line string, line_count integer, verdict enum OK/EMPTY, all required, additionalProperties: false.
• Same-turn evidence:
  • Served model: Claude ACP same-turn root model verification passed: requested=claude-sonnet-5-5 selector=default root_models=['claude-sonnet-5-5', 'claude-sonnet-5-5', 'claude-sonnet-5-5'] delegated_models=[]
  • Effort: ACP session config option verified: effort=medium
  • Read-only: session mode default, and the Write attempt was refused (ACP denying permission under read_only policy). The workspace was byte-identical afterwards and probe.txt was not created.
  • Native schema output: the provider emitted a StructuredOutput ACP tool call (pending → completed) with raw_input {"first_line":"sdk60 probe line one","line_count":3,"verdict":"OK"}.
  • get_agent_final_response(...), which backs the agent-server agent_final_response endpoint, returned exactly that JSON, and jsonschema.validate against the requested schema passed.
• Cleanup: no adapter processes left, and no .credentials.json left in the isolated runtime dirs.
• Tests: pytest tests/sdk/agent/test_acp_agent.py tests/sdk/conversation tests/sdk/settings gives 1247 passed; pre-commit (ruff, pycodestyle, pyright, import rules) passed.

Why

#58 qualified Claude Sonnet 5.5 but did not cover native schema structured output. Because of that, ai-dev-workflow-go#201 registered Sonnet 5.5 as prompt-only. This PR qualifies native json_schema output for the claude-sonnet-5-5 / medium / read-only / subscription OAuth tuple.

Summary

• There are no runtime changes. The existing Claude ACP outputFormat session metadata and the StructuredOutput final-response path are not model-specific, and the live run confirms they work for Sonnet 5.5.
• The fresh-session and resumed-session structured-output metadata tests now run for both exact models, claude-opus-5-5 and claude-sonnet-5-5, on the qualified read-only path. The alias + set_session_model path is still covered by test_claude_fresh_session_sends_meta_and_protocol_model.

Issue Number

Closes #60

How to Test

.venv/bin/python -m pytest -q tests/sdk/agent/test_acp_agent.py -k structured_output

Video/Screenshots

N/A

Design Doc

N/A (tests only)

Type

• Bug fix
• Feature
• Refactor
• Breaking change
• Docs / chore

Notes

Qualified tuple: claude-sonnet-5-5, effort medium, read-only, @agentclientprotocol/claude-agent-acp@0.81.0, subscription OAuth, native json_schema structured output PASS. A follow-up in geeen-jp/ai-dev-workflow-go will switch Sonnet 5.5 from prompt-only to native schema.

[github-actions]

Python API breakage checks — ✅ PASSED

Result: ✅ PASSED

Action log

[github-actions]

📁 PR Artifacts Notice

This PR contains a .pr/ directory with temporary PR-specific documents. The directory will be automatically removed when the PR is approved.

[github-actions]

REST API breakage checks (OpenAPI) — ✅ PASSED

Result: ✅ PASSED

Action log

[github-actions]

Endpoint audit

⚠️ 18 actionable Agent Server contract divergence(s) · report-only

Contract: pinned release artifact

Category	Count
Actionable client-only calls	0
Actionable server-only operations	18
Documented non-divergences	13
Agent Server contract operations	129
Audited handwritten client endpoints	119

Actionable client-only calls (0)

none

Actionable server-only operations (18)

• DELETE /api/canvas-extensions/installed/{}
• DELETE /api/llm/provider-connections/{}
• GET /api/canvas-extensions/installed
• GET /api/canvas-extensions/installed/{}
• GET /api/canvas-extensions/installed/{}/bundle
• GET /api/conversations/{}/events
• GET /api/file/archive
• GET /api/git/commits
• GET /api/git/commits/{}/changes
• GET /api/init
• GET /api/llm/provider-connections
• PATCH /api/canvas-extensions/installed/{}
• PATCH /api/llm/provider-connections/{}
• POST /api/canvas-extensions/install
• POST /api/conversations/{}/load_plugin
• POST /api/file/create_directory
• POST /api/init
• POST /api/llm/provider-connections

Documented non-divergences (13)

Client calls intentionally absent from the filtered contract (11)

• GET /
• GET /alive
• GET /health
• GET /ready
• GET /server_info

Reason: Operational Agent Server endpoints intentionally excluded from the filtered public release artifact.
Owner: OpenHands runtime maintainers

• DELETE /api/meta-profiles/{}
• GET /api/meta-profiles
• GET /api/meta-profiles/{}
• POST /api/meta-profiles/{}
• POST /api/meta-profiles/{}/activate

Reason: Client-ahead API stacked on the pending Agent Server meta-profiles implementation.
Owner: OpenHands SDK maintainers
Tracking: OpenHands#3744

• POST /api/profiles/{}/validate

Reason: Client-ahead API stacked on the pending Agent Server pre-flight LLM validation endpoint.
Owner: OpenHands TypeScript client maintainers
Tracking: OpenHands#4422

Server operations covered by an exposed browser URL (2)

• GET /api/conversations/{}/workspace
• GET /api/conversations/{}/workspace/{}

Reason: RemoteWorkspace.startWorkspaceSession exposes these authenticated URLs for browser iframe and file requests; they are not HttpClient method calls.
Owner: OpenHands TypeScript client maintainers

[github-actions]

Coverage Report •

File	Stmts	Miss	Cover	Missing
TOTAL	42723	11813	72%

report-only-changed-files is enabled. No files were changed during this commit :)