[Bug] Bridge mode: sub-agent spawned via sessions_spawn does not execute tasks

[Ivy-End]

Summary

When EVOLVE_BRIDGE=true (default), evolver spawns sub-agents via sessions_spawn, but the sub-agents do not execute any tasks. The sessions are created but remain idle with 0 tokens.

Environment

• OpenClaw: 2026.2.19-2
• Node: v22.22.0
• Evolver version: 1.14.0
• OS: Linux (iZ0xidzslypef6ccm1tkzuZ)

Steps to Reproduce

1. Set EVOLVE_BRIDGE=true (or unset, defaults to true)
2. Run node index.js run
3. Observe: sub-agent is spawned, but never executes
4. Check sessions - sub-agent shows 0 tokens, no activity

Expected Behavior

Sub-agent should receive the GEP prompt and execute the evolution tasks (apply patch, run validation, then run node index.js solidify)

Actual Behavior

• sessions_spawn returns accepted with valid childSessionKey
• Sub-agent session appears in sessions_list
• Sub-agent remains at totalTokens: 0 indefinitely
• Task never executes
• No errors in logs

Workaround

Set EVOLVE_BRIDGE=false in .env. This outputs the prompt directly to console, and manual execution of node index.js solidify works.

Additional Context

• Configured EVOMAP_HUB_URL and A2A_HUB_URL in .env
• Sub-agent configuration in openclaw.json:

  {
    "agents": {
      "defaults": {
        "subagents": {
          "maxConcurrent": 8
        }
      }
    }
  }

• Related OpenClaw issue: #5813 (agentToAgent.enabled breaks sessions_spawn) - but agentToAgent is not enabled in our config

Logs

[BRIDGE ENABLED] Spawning executor agent via sessions_spawn.
sessions_spawn({"task":"You are the executor (the Hand)...

The sub-agent is spawned but never starts executing.

[autogame-17]

Bridge mode (EVOLVE_BRIDGE=true) delegates execution to a sub-agent via sessions_spawn. This requires a wrapper/orchestrator (e.g., an IDE extension, OpenClaw, or a custom lifecycle manager) that can intercept and execute sessions_spawn calls.

When running evolver standalone (node index.js run), there is no external orchestrator to handle the spawn calls, so the sub-agents are created but nothing executes them.

Solutions:

1. Disable bridge mode: Set EVOLVE_BRIDGE=false to have evolver execute directly in-process
2. Use OpenClaw: OpenClaw handles sessions_spawn natively
3. Use --loop mode with bridge disabled: EVOLVE_BRIDGE=false node index.js run

This is by design -- bridge mode is an integration point, not a standalone feature. Closing with this explanation.