Add Pi and OMP harnesses with OMP as the default

[santoshkumarradha]

Product outcome

AgentField can now run Pi and OMP as first-class coding harnesses from Python, TypeScript, and Go. OMP is the consistent zero-configuration default, while explicit provider selection remains fully supported. A production-shaped Go example fans one task out to Pi and OMP concurrently and joins their typed results in a single AgentField workflow.

This closes the practical parity gap with OpenCode: applications use the same AgentField harness contract for model selection, project root, system prompt, tools, permissions, session resume, structured output, retries/timeouts, and normalized usage metrics.

Developer experience

• Provider resolution is identical in every SDK: per-call override → agent harness config → OMP.
• Model resolution is per-call override → agent config → the selected CLI's own configured default. The SDK no longer injects a Claude-specific sonnet fallback into provider-neutral calls.
• Explicit calls such as provider="opencode" or provider="pi" are unchanged.
• Provider-less usage attribution is now deterministic (harness=omp) across Python, TypeScript, and Go.
• Missing Pi/OMP executables produce actionable errors with the exact upstream install command.
• af harness doctor recognizes both CLIs, reports binary/version/auth/usability, and lists OMP first as the default.
• The README, provider guide, architecture design, shipped AgentField skill, and Go example document the default and operational lifecycle.

Architecture

• Adds a shared Pi-family adapter in each SDK with thin Pi/OMP flavor mapping instead of duplicating orchestration logic.
• Dispatches one-shot prompts through stdin and consumes JSON event streams, avoiding interactive CLI behavior.
• Maps AgentField's provider-neutral options to native CLI behavior:
  • model + #variant → --model + --thinking
  • project root → process cwd for Pi; --cwd plus process cwd for OMP
  • plan/auto → read-only tool filtering plus the provider's native approval flag
  • resume → Pi --session; OMP --resume
  • tool names → Pi find; OMP glob
• Reuses the existing isolated schema-file protocol and retry/validation orchestration used by the other harnesses.
• Normalizes sessions, turns, tokens, cache tokens, cost, model, duration, messages, return code, and failure classification into the existing result types.
• Keeps runtime installation outside SDK execution. Like Codex, Gemini, and OpenCode, operators install/pin the CLI in the host or image; AgentField only discovers, verifies, and invokes it. No application call mutates production hosts.

Parity assessment

Pi and OMP have feature parity with OpenCode at the AgentField contract boundary. Native flags are intentionally not identical: each adapter translates its CLI's approval, resume, project-root, and filesystem-search vocabulary. Those differences do not leak into application code.

Covered contract surface:

• model and reasoning variant
• project/cwd isolation and environment overrides
• system prompt and normalized tool allowlist
• plan and auto permission modes
• resumable sessions
• structured schema output with validation/recovery
• timeout and retry controls
• normalized token, cache, cost, session, turn, model, and duration metrics
• binary overrides and actionable availability failures

Installation and operations

npm install -g --ignore-scripts @earendil-works/pi-coding-agent
curl -fsSL https://omp.sh/install | sh
af harness doctor --provider pi,omp --json

The doctor check is static and does not make a paid model request. Containers should install the selected CLI during image construction and run the doctor as a startup/CI gate.

Go workflow example

examples/go_agent_nodes/cmd/harness_duo registers:

compare
├── pi_worker   (explicit Pi)
└── omp_worker  (provider omitted; exercises the OMP default)

compare starts both branches concurrently and joins their structured results. It defaults to openrouter/minimax/minimax-m2.7 and accepts openrouter/google/gemini-2.5-flash for a faster smoke path.

Verification

• Python: focused harness/types/usage suite passed; Ruff passed.
• TypeScript: 81 files / 832 tests passed; typecheck and production build passed.
• Go SDK: harness suite passed; changed agent/default/usage tests passed; example build passed.
• Control plane: CLI and embedded-skill tests passed; embedded skills are in sync.
• Final PR CI is green: 41 active checks passed across Go, Python, TypeScript, control-plane, Docker, local/Postgres functional tests, performance, aggregate/patch coverage, CodeQL, README links, and CLA (with only the expected AI-label job skipped).
• Live doctor: Pi 0.84.1 and OMP 17.2.15, both authenticated through OpenRouter and usable.
• Live AgentField execution: run_20260812_164308_d2tasl3y / exec_20260812_164308_fp15z9if succeeded in 19.4s with openrouter/google/gemini-2.5-flash; compare, pi_worker, and the provider-less omp_worker all completed with structured output and native cost/token metrics.
• Earlier MiniMax validation also succeeded for both branches: run_20260812_162041_fw7j8b54 with openrouter/minimax/minimax-m2.7.

Compatibility

Explicit provider configurations are unchanged. The intentional behavior change is that a call with neither a per-call nor configured provider now selects OMP instead of failing. Users who want another default can continue to set it once in HarnessConfig.

[github-actions]

Performance

SDK	Memory	Δ	Latency	Δ	Tests	Status
Python	9.0 KB	-	0.32 µs	-9%	✓	✓
Go	165 B	-41%	0.65 µs	-35%	✓	✓
TS	468 B	+34%	1.81 µs	-9%	✓	✗

⚠ Regression detected:

• TypeScript memory: 350 B → 468 B (+34%)

[github-actions]

📊 Coverage gate

Thresholds from .coverage-gate.toml: per-surface ≥ 84%, aggregate ≥ 85%, max per-surface regression ≤ 1.0 pp, max aggregate regression ≤ 0.50 pp.

Surface	Current	Baseline	Δ
control-plane	87.10%	87.40%	↓ -0.30 pp	🟡
sdk-go	92.80%	92.00%	↑ +0.80 pp	🟢
sdk-python	94.20%	93.73%	↑ +0.47 pp	🟢
sdk-typescript	91.11%	90.42%	↑ +0.69 pp	🟢
web-ui	84.76%	84.79%	↓ -0.03 pp	🟡
aggregate	85.62%	85.75%	↓ -0.13 pp	🟡

✅ Gate passed

No surface regressed past the allowed threshold and the aggregate stayed above the floor.

[github-actions]

📐 Patch coverage gate

Threshold: 80% on lines this PR touches vs origin/main (from .coverage-gate.toml:thresholds.min_patch).

Surface	Touched lines	Patch coverage	Status
control-plane	2	100.00%	✅
sdk-go	247	91.00%	✅
sdk-python	0	—	➖ no changes
sdk-typescript	123	89.00%	✅
web-ui	0	—	➖ no changes

✅ Patch gate passed

Every surface whose lines were touched by this PR has patch coverage at or above the threshold.

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