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Crucible

Agent Configuration

Crucible runs AI agents through two complementary systems:

  1. Chat agents ([chat]) — Crucible’s own REPL agent backed by one of the configured LLM providers.
  2. ACP agents ([acp]) — external agents (Claude Code, OpenCode, Gemini, etc.) hosted via the Agent Client Protocol.

LLM provider credentials and endpoints live in [llm]; this page covers the two agent-selection sections.

Configuration Location

Agent settings live in ~/.config/crucible/config.toml, or in whatever file you point -C / $CRUCIBLE_CONFIG at. A kiln’s .crucible/ directory holds kiln.toml, which carries only the kiln’s display name — [chat] and [acp] are not read from there.

[chat] — Chat Defaults

Applied when you run cru chat without --acp or --provider.

[chat]
# Override the default model (otherwise inherited from the default provider)
model = "llama3.2"


# Prefer external ACP agents or Crucible's built-in agent
# Values: "acp" or "crucible" (default)
agent_preference = "crucible"


# Override provider endpoint for Ollama/compatible
# endpoint = "http://localhost:11434"


# Generation controls (optional)
# temperature = 0.7
# max_tokens = 4096


# Stream thinking/reasoning tokens below the spinner
show_thinking = false

The actual provider default lives under [llm]:

[llm]
default = "ollama"          # key from [llm.providers.*]


[llm.providers.ollama]
type = "ollama"
default_model = "llama3.2"

See [llm] for the full provider reference.

[acp] — ACP Agent Defaults

Applied when you run cru chat --acp <name> or bring up the agent picker.

[acp]
# Default ACP agent to use when --acp is omitted (optional)
default_agent = "opencode"  # or "claude", "gemini", "codex", "cursor", "hermes"


# Streaming response timeout in minutes
streaming_timeout_minutes = 15

The removed fields lazy_agent_selection, enable_discovery, session_timeout_minutes and max_message_size_mb still load without an error; the values are ignored. See acp.

Custom ACP Agent Profiles

Extend a built-in agent profile with additional environment or arguments under [acp.agents.<name>]:

[acp.agents.my-claude]
extends = "claude"
env = { ANTHROPIC_BASE_URL = "http://localhost:4000" }

The extended name is then selectable via cru chat --acp my-claude.

See acp for every field on [acp] and [acp.agents.<name>], including delegation and per-agent permissions.

See Also