Tier-1 Capability Matrix

Tier-1 harnesses: Claude Code · Codex · OpenCode · Pi Mono

Tier-2 harnesses (tracked, not blocking): Copilot · Gemini · Kimi

Legend:

• ✅ Universal codegen — adapter emits native output automatically from the manifest
• ⚠️ Guided per-harness — no native primitive; author follows a documented escape-hatch pattern; emits a WARN (not error) on portable manifests
• ❌ Unsupported — no viable path; recorded here, not blocking
• n/a — not applicable (mechanism differs but functionality is covered)

Capability table

Capability	Claude Code	Codex	OpenCode	Pi Mono	Notes
skills	✅	✅	✅	✅	Universal codegen
hooks (lifecycle)	✅	✅	✅	✅	Universal codegen
commands	✅	✅	✅	✅	Universal codegen
mcpServers	✅	✅	✅	✅	Recommended universal tool path
agents[]	✅	✅	✅	✅	Universal codegen
subagentStart	✅	✅	⚠️	✅	OpenCode: no native event; emits WARN; guided path: intercept via preToolUse for subagent tool
subagentStop	✅	✅	⚠️	✅	Same as above; Pi stop↔subagentStop collision fixed in v0.3.0
tools[] (first-class)	⚠️	⚠️	✅	✅	WARN emitted; use mcpServers for Claude/Codex (Tier-1 universal tool path)
stop / continueWith	⚠️	⚠️	⚠️	⚠️	New primitive — v0.4.0; all-Tier-1 design
Native-entry passthrough	n/a (JSON)	n/a (JSON)	⚠️	⚠️	nativeEntry escape hatch — v0.4.0
spawnChild subprocess	✅ via cmd	✅ via cmd	⚠️	⚠️	Primitive set — v0.4.0

Tier-2 footnotes

Capability	Copilot	Gemini	Kimi
skills	✅	✅	✅
hooks (lifecycle)	⚠️	⚠️	❌
subagentStart / subagentStop	❌	❌	❌
tools[]	✅	✅	❌
mcpServers	❌	❌	❌

Kimi hooks remain in UNSUPPORTED_HOOKS (packages/adapter-kimi/src/index.ts); tracked here, not blocking v0.3.0.

Decision tree for authors

Does universal codegen cover this capability across all Tier-1?
  YES → use it; adapter handles the rest
  NO  → is there a custom (escape-hatch) path on all Tier-1?
    YES → follow the guided per-harness pattern (see "Rewriting for tier-1 parity" guide)
    NO  → is the gap TUI-grade fidelity only?
      YES → acceptable degradation; note in this matrix
      NO  → open a primitive proposal (v0.4.0+ scope)

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This matrix is the living contract for the project. Update it as capabilities land or gaps are discovered. See the PRD roadmap for full context.