# Agent Tuning

> Use when changing agent model or effort configuration, adapter mappings, or eval candidate profiles.

- Skill: `mvanhorn/agent-tuning` (Agent Skill)
- Install (CLI): `npx skillmds@latest add mvanhorn/agent-tuning`
- Raw SKILL.md: https://api.skillmd.com/api/skills/mvanhorn/agent-tuning/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: AI & ML
- Author: mvanhorn (https://skillmd.com/u/mvanhorn)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/mvanhorn/agent-tuning

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**Unified Agent Tuning (`internal/agentcfg`)**

- `agentcfg` is the single owner of the harness-neutral model/effort surface and of the mapping down to each harness's native mechanism (claude/copilot `--effort`, codex `-m` + `-c model_reasoning_effort`, grok `--reasoning-effort`, pi `--thinking`, opencode's session-message `model`/`variant`, acpx `--model` for `cursor`/`acp:<target>`). Add a harness there, not in an adapter or in eval. `rovodev` and `antigravity` are deliberately declared unmappable, so a request for them is a config error rather than a flag that is silently ignored.
- `agent.NewWithOptions` is the one funnel: it validates `Options.Profile` and splices the mapped args after the operator's raw `agent_args_override` args, so both the pipeline (`cfg.AgentProfileFor`) and eval replay (`Candidate.Profile()`) reach every harness by the same path. Never re-derive a model or effort flag at a call site.
- Precedence is fixed: a raw `agent_args_override` flag that already pins a knob natively wins and the mapped value is not emitted, which is what keeps every pre-`agent_config` configuration byte-identical and stops a harness receiving one knob twice. `agent_config` is global-only for the same reason as `agent_args_override`.
- Eval candidates are `agent,model=<model>[,effort=<level>]` (the previous `agent+model` spelling is refused with a migration message), effort is part of the persisted candidate identity, and `agentNeutralGlobalConfig` strips `agent`, `agent_args_override`, and `agent_config` so a replay never inherits the capturing machine's pins.
- Regressions: `internal/agentcfg`, `internal/agent/profile_test.go`, `internal/config/config_agent_config_test.go`, `internal/daemon/pipeline_agent_profile_test.go`, `TestParseCandidate*`, `TestReplayPinsCandidateModelAndEffortOnTheHarness`, `TestCaptureStripsEveryHarnessPinFromThePinnedConfig`.