evolve_apply

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Far exceeds the annotations (readOnlyHint=false, idempotentHint=false, destructiveHint=false). It discloses the spawned child, the exact file edited (render_brief() in brief.py), the test requirement, the full-suite gate, the PR-only guarantee ('NEVER pushes or commits to main'), the autoland/squash-merge behavior, the THREADKEEPER_EVOLVE_AUTOLAND=0 escape hatch, and the applied=1 autonomy gate. This is rich, non-obvious behavioral context.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with the core action, then the lifecycle and preconditions. Dense and largely waste-free, though the parenthetical asides (autoland, status-line format) add length that could be trimmed without loss.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a high-complexity tool that spawns a child, edits code, runs tests, and opens a PR, the description covers the full lifecycle, the autonomy gate, preconditions, and failure modes. An output schema exists, so return-value detail needn't be explained, yet the status-line format is still noted.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0% for the single required evolve_id parameter, so the description must compensate — and it does, explaining the id's provenance (from evolve_review()) and its validity constraints (must exist and be promoted+unapplied). It adds real meaning beyond the bare integer type.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb+resource and scope: 'Implement a PROMOTED + not-yet-applied format-evolution suggestion.' It is clearly distinguishable from siblings like evolve_review (source of ids), evolve_mark_applied (the reporting step), and evolve_decide. An agent can tell exactly what this does without opening any schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives concrete preconditions (id must exist and be promoted+unapplied), names the source of ids ('Get ids from evolve_review()'), and states the single-flight constraint. It does not enumerate explicit when-not-to-use alternatives, but the eligibility rules effectively cover the routing decision.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.