repair-opencode-json.py: orphaned empty agent.build/plan blocks survive #60 prompt migration and silently break dm-agent-sync

[chubes4]

Summary

After the #60 prompt migration moves agent.build.prompt → top-level instructions[], the now-empty agent.build / agent.plan blocks (containing only mode + model) are intentionally preserved. Those default-equivalent shells then prevent dm-agent-sync.ts from registering DM agent prompts into build/plan, so new sessions launch as the bare build agent without AGENTS.md, SOUL.md, MEMORY.md, etc.

Repro

1. Fresh install of wp-coding-agents 0.8.1 with --chat-bridge=kimaki on a site with multiple DM agents.
2. Inspect the generated opencode.json. (On this VPS — /var/www/extrachill.com/opencode.json — it contained:)

   "agent": {
     "build": { "mode": "primary", "model": "anthropic/claude-opus-4-7" },
     "plan":  { "mode": "primary", "model": "anthropic/claude-opus-4-7" }
   }

3. Start a Kimaki session in that project.
4. Ask the agent what's in its system prompt. It will not be aware of AGENTS.md, SOUL.md, MEMORY.md, or the WordPress runtime / Data Machine handoff sections that dm-context-filter injects.

Root cause

lib/repair-opencode-json.py::apply_prompt_migration (lines 190–221) deliberately leaves agent.build / agent.plan in place after stripping prompt:

# Clean up empty dicts.
for sub in ("build", "plan"):
    if sub in agent and isinstance(agent[sub], dict) and not agent[sub]:
        pass  # keep mode/model keys

Combined with dm-agent-sync.ts line 129:

if (config.agent.build && config.agent.plan && agents.length === 1) {
  // ... only updates prompt for the single-agent case
}

…multi-agent installs (10 agents on this site) skip the prompt-injection branch entirely. The orphaned shells "win" because they look like user config to the plugin, even though they only carry default-equivalent keys.

Why it matters

This is the second-order regression of #60. The original fix correctly moved memory loading out of agent.build.prompt (preserving Claude Max OAuth), but didn't reconcile that agent.build / agent.plan entries with only mode + model are now no-ops at best and footguns at worst. They serve no purpose — mode: primary and the top-level model are already the OpenCode defaults.

Result on this VPS: every Kimaki session for a month has launched without AGENTS.md in context, despite the file being 9.7 KB of curated Data Machine / Homeboy / Extra Chill CLI documentation.

Proposed fix

In apply_prompt_migration (or a new clean_orphaned_agents step), after stripping prompt, also remove the build / plan entries entirely if they only contain default-equivalent keys (mode: primary and/or a model that matches the top-level model):

top_model = data.get("model")
for sub in ("build", "plan"):
    block = agent.get(sub)
    if not isinstance(block, dict):
        continue
    keys = set(block.keys())
    is_default_only = keys <= {"mode", "model"} and \
                      block.get("mode", "primary") == "primary" and \
                      block.get("model", top_model) == top_model
    if is_default_only:
        del agent[sub]
if not agent:
    data.pop("agent", None)

runtime_generate_config() in runtimes/opencode.sh should also stop emitting these blocks for new installs — they're already removed from runtime_generate_config per #60, but this needs a confirmation pass.

Test plan

• Existing opencode.json with agent: { build: { mode, model }, plan: { mode, model } } → --additive removes the orphaned blocks, prompt migration unchanged.
• User-customized agent.build (e.g. with custom tools or non-default mode) → preserved untouched.
• After repair, fresh OpenCode session with multiple DM agents loads AGENTS.md + agent identity files via dm-agent-sync.

Related

• fix(opencode): use instructions array, not agent.build.prompt #60 — original prompt migration that left this behind
• Companion bug filed for dm-agent-sync.ts user-override detection (link will follow)

Environment

• wp-coding-agents 0.8.1 (commit b7e5acb)
• VPS: /var/www/extrachill.com, 10 DM agents, Kimaki bridge
• Discovered while investigating why an OpenCode session was not aware of the project's AGENTS.md