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

The annotations already mark this as a non-read-only, non-idempotent, non-destructive action; the description adds meaningful behavior on top by disclosing two failure modes and the effect on triggers/new runs. It does not contradict the annotations, though it could have clarified what happens to the previous live revision.

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?

Two tight sentences: the first states the action, the second adds the consequence and failure conditions. There is no filler or redundancy, and the most important operational constraint is front-loaded.

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 small mutation tool with no output schema, the description covers the action, its purpose, and key failure cases; optional parameters are fully documented in the schema. The only minor gaps are definitional context around what qualifies as a draft/historic revision and the exact relationship between build_id and the revision being promoted.

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?

The schema has 100% parameter description coverage, so the baseline is 3. The tool description adds no parameter-level detail beyond the schema, and it leaves the relationship between build_id and 'revision' implicit, but the schema's own property descriptions cover the three fields adequately.

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?

The description uses a specific verb and object: 'Promote a draft or historic revision to the live version.' It also defines what 'live' means ('used by triggers and new runs'), making the tool's purpose unmistakable and distinct from read/update revision tools.

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?

It gives clear when-to-use context: promotion is needed to make a revision live for triggers and new runs. It also provides when-not conditions by stating the call fails if the revision is already live or a draft still has an active builder run. It does not explicitly name sibling alternatives like promoteSkillRevision, so it falls just short of a 5.

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