fix: remove retired homeboy-codebox-agent-tasks AGENTS.md guidance on sync

[chubes4]

Fixes #609.

What was actually wrong

The issue describes four duplicated paragraphs inside the composed ## Homeboy section (**Codebox executor:**, **WP Codebox agent mode:**, **Codex provider:**, **Claude Code provider:**) that repeat detail already owned by the standalone ## WP Codebox section. I went looking for the guidance source that renders them (guidance/homeboy.sh, per the section marker agents-md-guidance:homeboy-cli) and it doesn't produce that content — guidance/homeboy.sh only emits Default routing / Operator boundary / Control-plane recovery / Discovery.

git log --all -S"homeboy-codebox-agent-tasks" found the real source: PR #246 (commit eefb2c0, "fix: keep Homeboy AGENTS guidance lean") deliberately deleted agents_md_guidance_sync_homeboy_codebox() and its call site in lib/homeboy.sh, retiring the whole homeboy-codebox-agent-tasks section (registered separately from homeboy-cli, under its own marker, immediately following it in the composed doc). That commit stopped producing the section going forward, but never unregistered it from installs that had already synced it — there is no code path left anywhere in this repo that calls agents_md_guidance_unregister "homeboy-codebox-agent-tasks". extrachill.com synced before #246 landed, so it has been re-emitting the orphaned block on every compose since, with no producer to edit and no way for a future sync to clean it up.

The four paragraphs named in the issue:

• **Codebox executor:**
• **WP Codebox agent mode:**
• **Codex provider:**
• **Claude Code provider:**

are four of the eight paragraphs in that same orphaned section (the other four — **Agent tasks:**, **Workspace shape:**, **Operator verbs:**, **Chat bridges:** — were retired by the identical #246 decision for the identical reason). There is no live source anywhere in the codebase to surgically edit "4 of 8" back down to a one-liner; the entire section is dead code with zero producer. Rebuilding a new guidance unit to keep 4 of those 8 paragraphs alive would mean reintroducing content #246 explicitly chose to delete for being too heavy, which is the opposite of the fix. So this closes the actual gap #246 left behind: the whole retired section is now unregistered on sync, converging stale installs to the same state a fresh install already has.

Byte count removed on extrachill.com: ~2,028 bytes of always-on Homeboy-embedded WP Codebox context per the issue's measurement (the full retired section, not just the four named paragraphs — see above for why the other four go with it).

Layer-purity rationale

Homeboy is the orchestration layer; it must not document the provider-credential surface of a layer below it. Provider secret names like AI_PROVIDER_OPENAI_CODEX_* and AI_PROVIDER_CLAUDE_CODE_REFRESH_TOKEN belong to whoever owns the provider (WP Codebox / the carried provider plugin), not to Homeboy. The standalone ## WP Codebox section already documents sandbox recipes, providers, and credentials; Homeboy's job is only to know Codebox is an available executor backend.

What changed

• lib/homeboy.sh: sync_homeboy_agents_md_guidance() now also calls a new homeboy_retired_codebox_agents_md_guidance_remove(), which unconditionally calls agents_md_guidance_unregister "homeboy-codebox-agent-tasks". Unregister is already idempotent (no-op when the section isn't present), so this is safe on every install — fresh installs that never had the section, installs still on it, and installs already cleaned up.
• tests/agents-md-guidance.sh: new regression case that registers a fixture reproducing the retired section (all eight legacy paragraphs, including the secret-name strings), runs sync_homeboy_agents_md_guidance, and asserts the block is gone, the current homeboy-cli section is untouched, the mu-plugin still parses (php -l), and a second sync is a no-op (idempotent).

Explicitly out of scope / unchanged

• The ## WP Codebox section itself — owned by a different plugin, not touched.
• No command documentation changed. Every command in the current homeboy-cli guidance (homeboy agent-task cook, homeboy agent-task fanout cook-batch, homeboy agent-task controller, homeboy config show, etc.) is untouched; this is not a staleness fix.
• The Homeboy operator-boundary text and control-plane recovery steps in guidance/homeboy.sh are untouched.

Verification

• bash tests/agents-md-guidance.sh — all assertions pass, including the new retired-section regression case.
• bash tests/homeboy-components.sh, tests/homeboy-project-id.sh, tests/homeboy-verification-guidance.sh, tests/homeboy-codebox-canary.sh, tests/workspace-installation.sh — all pass (no regressions in adjacent Homeboy coverage).
• bash -n lib/homeboy.sh — syntax check clean.
• No PHP files were hand-edited (the mu-plugin is generated); the new test's php -l assertion on the generated mu-plugin passes before and after cleanup.

🤖 Generated with the assistance of an AI coding agent.