Harness Adapters

A harness is the coding environment Tuff emits into, such as .agents/ or .claude/. A harness adapter is Tuff’s agent-specific implementation layer for that environment.

The adapter decides where files are emitted, how native settings are updated, and where tool registration lives.

Supported Adapters

Tuff currently ships four adapters:

Adapter	Target id	Main output root
Open Agents	`open-agents`	`.agents/`
Claude	`claude`	`.claude/`
Codex	`codex`	`.agents/`
Cursor	`cursor`	`.cursor/`

open-agents remains the generic shared .agents/ adapter. Codex now has a dedicated adapter even though it currently emits the same directory family, because its hook coverage and native behavior are tracked independently.

Legacy aliases are also accepted:

claude-code resolves to claude

The same capability can be emitted differently depending on the agent.

Skills

Agent	Emitted path
`open-agents`	`.agents/skills/<id>/...`
`claude`	`.claude/skills/<id>/...`

Tools

Agent	Emitted path	MCP registration
`open-agents`	`.agents/tools/<id>/...`	`.agents/mcp.json`
`claude`	`.claude/tools/<id>/...`	`.mcp.json`
`codex`	`.agents/tools/<id>/...`	`.agents/mcp.json`
`cursor`	`.cursor/tools/<id>/...`	`.cursor/mcp.json`

Tuff writes the tool files and also registers the tool in the agent’s MCP config so the harness can discover it.

Hooks

Hooks are where the adapter differences are most visible:

Agent	Emitted path	Format
`open-agents`	`.agents/hooks/<id>/run.sh` plus `.agents/hook.json`	Native JSON (development format)
`claude`	`.claude/hooks/<id>/...` plus `.claude/settings.json`	Native Claude JSON
`codex`	`.agents/hooks/<id>/run.sh` plus `.agents/hook.json`	Codex hook JSON
`cursor`	`.cursor/hooks/<id>/run.sh` plus `.cursor/hooks.json`	Cursor Hooks JSON

For Claude, tuff add hook ... --hook-file settings.json reads a hooks-only native fragment, copies runtime files when needed, and merges the fragment into .claude/settings.json.

Workflows

Target	Emitted path
`open-agents`	`.agents/workflows/<id>/workflow.toml`
`claude`	`.claude/workflows/<id>/workflow.toml`
`codex`	`.agents/workflows/<id>/workflow.toml`
`cursor`	`.cursor/workflows/<id>/workflow.toml`

Supported capability types

All four adapters currently support:

skill
tool
hook
workflow

Supported hook events

Manifest-style Tuff-standard hook event support is adapter-specific. Native hook fragments supplied with --hook-file keep their harness event names and are merged as-is.

Event	`open-agents`	`claude`	`codex`	`cursor`
`before_finish`	Yes	Yes	Yes	Partial, rendered as `stop`
`after_save`	Yes	No	Yes	No
`pre_tool_use`	Yes, rendered as `pre_tool_execution`	No	Partial, rendered as `pre_tool_execution`	Yes, rendered as `preToolUse`
`post_tool_use`	Yes, rendered as `post_tool_execution`	Yes, rendered as `post_tool_execution`	Partial, rendered as `post_tool_execution`	Yes, rendered as `postToolUse`
`session_start`	No	Yes, rendered as `SessionStart`	No	Yes, rendered as `sessionStart`
`session_end`	No	No	No	Yes, rendered as `sessionEnd`
`stop`	No	No	No	Yes, rendered as `stop`

Codex and Cursor have dedicated compatibility rows even when their output roots overlap with the generic Open Agents adapter. Cursor renders native names such as sessionStart, preToolUse, postToolUse, and stop into .cursor/hooks.json.

If you try to install a manifest-style hook with an unsupported event, Tuff blocks the install and shows which events that adapter accepts. Run tuff hooks matrix to inspect the registered adapter compatibility matrix, or tuff hooks check-portability <id> --target <adapter> to check an installed hook before switching adapters.

Commands

tuff agent list
tuff agent add open-agents
tuff agent add claude
tuff agent add codex
tuff agent add cursor
tuff hooks matrix