[docs] Update documentation for features from 2026-04-21

[github-actions]

Documentation Updates - April 21, 2026

This PR updates the documentation based on features merged in the last 24 hours.

Features Documented

• OpenCode engine (from Add experimental OpenCode engine support, smoke workflow, and reassign LLM gateway ports #27466) — Added to the engines reference table, feature comparison, version pinning table, and timeout summary.
• engine.driver field (from Add configurable agentic engine driver script support #27453) — New frontmatter field for replacing the built-in Copilot driver script with a custom Node.js script.
• Network identifier validation (from Error on unknown single-word ecosystem identifiers in network.allowed #27475) — Compile-time error on unknown single-word ecosystem identifiers in network.allowed.
• Removed stale migration entry — Removed the incorrect engine:id:opencode removed entry from upgrading.md (OpenCode is now a supported engine).

📝 Detailed Changes & References

Changes Made

• Updated docs/src/content/docs/reference/engines.md:
  • Added opencode (experimental) to the Available Coding Agents table
  • Added opencode column to the Engine Feature Comparison table
  • Added engine.driver row to the feature comparison table
  • Added opencode to the version pinning table
  • Added opencode column to the Timeout Summary table
  • Added new Custom Driver Script (driver) section documenting engine.driver
• Updated docs/src/content/docs/reference/network.md:
  • Added Ecosystem Identifier Validation subsection explaining compile-time errors for unknown single-word identifiers
• Updated docs/src/content/docs/guides/upgrading.md:
  • Removed stale "Manual Migrations" section that incorrectly stated opencode was removed

Merged PRs Referenced

• Add experimental OpenCode engine support, smoke workflow, and reassign LLM gateway ports #27466 — Add experimental OpenCode engine support, smoke workflow, and reassign LLM gateway ports
• Add configurable agentic engine driver script support #27453 — Add configurable agentic engine driver script support
• Error on unknown single-word ecosystem identifiers in network.allowed #27475 — Error on unknown single-word ecosystem identifiers in network.allowed

Skipped Issues

• Provider-based authentication for Claude, Copilot, Codex. #16498 (BYOK COPILOT_PROVIDER_* vars) — Confirmed as an ongoing gap; requires a larger documentation effort across auth.mdx, engines.md, and environment-variables.md. Deferred to a dedicated PR.
• Meet the workflows points to specific versions, need to keep these up to date #20391 (stale v0.45.5 blog links) — Requires automated tooling to update 115 occurrences across 18 blog posts. Out of scope for this run.
• Remove imports.apm-packages from workflow schema and schema-driven docs #27493 (imports.apm-packages removal) — Documentation was already updated in the PR itself (frontmatter-full.md updated).
• Support extending safe_outputs dependencies via safe-outputs.needs #27476 (safe-outputs.needs) — Documentation was already updated in the PR itself (safe-outputs.md updated).
• Fail loudly when preserve-branch-name collides with existing remote branch #27458 (preserve-branch-name collision) — Documentation was already updated in the PR itself (safe-outputs-pull-requests.md updated).

Generated by Daily Documentation Updater · ● 572.4K · ◷

• expires on Apr 22, 2026, 11:03 AM UTC

[github-actions]

Hey @github-actions — great automated documentation pass for the April 21 features! The coverage is thorough: the OpenCode engine additions, engine.driver field docs, ecosystem identifier validation, and the stale migration cleanup are all well-explained with examples.

One mechanical flag from the checklist:

• No test files changed — the checker flagged this as needs-work, but that's expected for a pure documentation PR (only .md files in docs/ are touched). No action needed on this point.

If you'd like to suppress this flag in future runs, you could add a lightweight docs-linting or link-validation step so the checker detects "test-equivalent" coverage for documentation PRs:

Add a docs validation step to the Daily Documentation Updater workflow that runs after generating the PR.
The step should:
1. Run `make docs-lint` (or equivalent) to verify all internal links in the changed .md files resolve correctly.
2. Check that any new engine entries in engines.md have a corresponding row in every reference table (feature comparison, version pinning, timeout summary).
This ensures documentation PRs have automated coverage checks analogous to unit tests for code PRs.

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