feat: activate coordinator mode in open build

[Flo5k5]

Summary

Activate the full multi-agent system in the open build: coordinator mode, worker agents, and built-in Explore/Plan agents.

Highlight: agent nesting unlocked

The most impactful change is a single line removed in src/constants/tools.ts:41 (PR #644):

...(process.env.USER_TYPE === 'ant' ? [] : [AGENT_TOOL_NAME]),

This line added AGENT_TOOL_NAME to the disallowed tools list for sub-agents, preventing non-ant users from using recursive agent workflows. Removing it unlocks recursive agent spawning: a sub-agent can now spawn its own sub-agents. This enables complex coordination patterns (agent teams, hierarchical delegation) that were previously reserved for Anthropic employees.

Changes (3 commits)

1. Coordinator mode activated (scripts/build.ts, src/coordinator/workerAgent.ts)

• Enable COORDINATOR_MODE: true build flag
• Create workerAgent.ts — the only missing module from the source snapshot
• Includes WORKER_AGENT with agentType: 'worker' to match the coordinator system prompt's subagent_type: "worker" instructions

2. Explore and Plan agents activated (scripts/build.ts)

• Enable BUILTIN_EXPLORE_PLAN_AGENTS: true build flag
• Makes Explore (fast, haiku, read-only) and Plan (architect, read-only) agents available in both normal and coordinator modes
• Resolves the inconsistency where coordinator workers had these agents but normal sessions did not

What is coordinator mode?

A multi-agent orchestration system:

• A coordinator receives the user's task and decomposes it into sub-tasks
• It spawns workers via AgentTool that execute in parallel
• Workers communicate back via SendMessageTool, coordinator can stop them with TaskStopTool
• A 252-line system prompt guides the coordinator's orchestration strategy
• Session mode persists across restarts

Runtime activation

Coordinator mode is opt-in at runtime:

export CLAUDE_CODE_COORDINATOR_MODE=1

Explore and Plan agents are always available (no env var needed).

Optional scratchpad for cross-worker knowledge sharing:

// ~/.claude/feature-flags.json (requires #639)
{ "tengu_scratch": true }

Relationship to other PRs

• feat: open useful USER_TYPE-gated features to all users #644 (agent nesting) — compatible: coordinator has its own COORDINATOR_MODE_ALLOWED_TOOLS
• feat: local feature flag overrides via ~/.claude/feature-flags.json #639 (local feature flags) — enables tengu_scratch scratchpad and tengu_amber_stoat control
• cleanup: remove dead USER_TYPE branches from non-stubbed modules #637 (dead code) — no overlap with coordinator files

Test plan

• bun run build — compiles successfully
• bun run smoke — smoke tests pass
• Set CLAUDE_CODE_COORDINATOR_MODE=1, verify coordinator system prompt loads
• Spawn a worker agent with subagent_type: "worker", verify it resolves
• Verify Explore and Plan agents appear in /agent list
• Test session resume preserves coordinator mode
• Verify coordinator mode is inactive by default (no env var = normal mode)

[Copilot]

Pull request overview

Enables the open-build COORDINATOR_MODE feature flag and adds the missing coordinator worker agent module so coordinator-mode wiring can resolve at build/runtime.

Changes:

• Added src/coordinator/workerAgent.ts to supply coordinator-mode agent definitions.
• Enabled COORDINATOR_MODE: true in scripts/build.ts so coordinator-mode code is included in open builds.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
src/coordinator/workerAgent.ts	Adds getCoordinatorAgents() used by builtInAgents.ts when coordinator mode is active.
scripts/build.ts	Flips the open-build flag to include coordinator-mode code paths in the bundled output.

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[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

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