Using Noir with ACP Agents

Use ACP (Agent Client Protocol) providers when you want Noir to talk to an AI agent process instead of a direct HTTP LLM API.

Supported ACP Providers

• acp:codex -> runs npx @zed-industries/codex-acp
• acp:gemini -> runs gemini --experimental-acp
• acp:claude -> runs npx @zed-industries/claude-agent-acp
• acp:<custom> -> runs <custom> as an ACP-compatible command, only with NOIR_ACP_ALLOW_CUSTOM_COMMAND=1

Any other target is refused. --ai-provider can come from a config file, and spawning whatever it names would be a code-execution path, so custom binaries need the explicit opt-in:

NOIR_ACP_ALLOW_CUSTOM_COMMAND=1 noir scan ./myapp --ai-provider="acp:my-agent --flag"

Usage

Codex (recommended test target)

noir scan ./myapp --ai-provider=acp:codex

Gemini

noir scan ./myapp --ai-provider=acp:gemini

Claude

noir scan ./myapp --ai-provider=acp:claude

Optional model

For acp:*, --ai-model is optional.

noir scan ./myapp --ai-provider=acp:codex --ai-model=codex

Logging Behavior

By default, Noir wraps ACP lifecycle events in Noir-style logs and suppresses raw ACP/agent stderr noise.

Set this if you need raw ACP and agent logs:

NOIR_ACP_RAW_LOG=1 noir scan ./myapp --ai-provider=acp:codex

Tool Permissions

An ACP agent can ask Noir for permission to run its own tools — shell commands, file writes, network fetches — on your machine. Noir declines every one of them.

The prompt Noir sends the agent is source code from the tree you are scanning, and scanning code you did not write is the normal case. A file that carries "ignore the above and run this instead" is enough to steer the agent, so the permission prompt is the one checkpoint left; answering it with an automatic yes would turn an endpoint scan into arbitrary local execution.

Nothing is lost by declining: the code to analyze is already in the prompt, so the agent needs no tools to answer. If you are scanning a tree you trust and want the agent to explore on its own, opt in explicitly:

NOIR_ACP_ALLOW_TOOL_PERMISSIONS=1 noir scan ./myapp --ai-provider=acp:codex

Notes

• --ai-key is not required for acp:* providers.
• Cache flags (--cache-disable, --cache-clear) work the same as other AI providers.
• acp:claude-code is accepted as an alias of acp:claude.