Agents

An agent is a named configuration that binds a model to a system prompt, tools, and behavior settings. The daemon can run many agents simultaneously — each with its own model, personality, and capabilities.

Default agent

The [system.crab] section configures the daemon's built-in agent:

[system.crab]
model = "deepseek-chat"
thinking = false

This is the agent you get when you run crabtalk without arguments.

Custom agents

Define additional agents in [agents.<name>] sections:

[agents.researcher]
description = "Deep research specialist"
model = "claude-sonnet-4-20250514"
max_iterations = 32
thinking = true
members = ["writer"]
skills = ["web-research"]
mcps = ["search"]

System prompts

Each agent loads its system prompt from ~/.crabtalk/local/agents/<name>.md. Create the file to give an agent its personality and instructions:

echo "You are a research specialist. Be thorough and cite sources." \
  > ~/.crabtalk/local/agents/researcher.md

The default agent's identity is embedded in the binary. You can override it globally by creating ~/.crabtalk/Crab.md, or per-project with a Crab.md in the project root.

Delegation

When an agent has members, it can spawn tasks for those agents. The researcher above can delegate writing tasks to the writer agent. Tasks track state (queued, in progress, blocked, finished, failed) and respect concurrency limits.

Scoping

Control what each agent can access:

• skills = ["name1", "name2"] — only these skills are available. Empty list means all skills.
• mcps = ["name1", "name2"] — only these MCP servers' tools are available. Empty list means all.

Scoping keeps agents focused and prevents them from using tools outside their responsibility.

Session titles

After the first exchange in a conversation, the daemon auto-generates a short title (3-6 words) using the active model. Titles appear in the session browser (/resume in the REPL) and are included in the session filename.

Auto-compaction

When a conversation exceeds the token threshold set by compact_threshold, the agent automatically compacts the history — summarizing earlier messages to stay within the context window. Configure it in [system.crab]:

[system.crab]
compact_threshold = 100000

On compaction, earlier messages are condensed into a dense prose summary. The summary preserves agent identity, user profile, key decisions, and active tasks. Session files on disk retain full history — compaction only affects the context window.

What's next

• Multi-Agent Setup — step-by-step delegation guide
• Skills — how skills extend agent behavior
• Memory — how agents remember across sessions