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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and closed-world behavior, so the baseline burden is low. The description still adds genuine value: the required OAuth scope (projects:read), the guarantee that no credential is ever returned, and the shape of the proof record. It stops short of describing pagination or ordering, but for a small status call that is minor.

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?

Four compact sentences, front-loaded with what is returned and followed by the slot hint, the security guarantee, and the scope. The opening is a sentence fragment and the comma-spliced listing ('email, errors, ...') is slightly rough, but no sentence is wasted.

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?

With no output schema, the description carries the return-shape burden and does so by naming the proof record fields and the live/not-live signal. Combined with schema-documented defaults for branch, project_id and organization_id, an agent has enough to call it correctly; only the relationship to addon.status remains unexplained.

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 100%, and each parameter already documents its default and meaning, so the schema does the heavy lifting. The only addition is 'Pass `slot` for one', which essentially restates the slot parameter's own documentation, and the inline examples (email, errors) duplicate schema examples.

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 names the resource precisely (one-command add-ons a branch has) and the exact information returned (live status plus a proof record {kind, id, at}), so an agent knows what it gets. It does not, however, differentiate itself from the sibling addon.status, which an agent could easily confuse with capabilities.status.

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?

Usage is implied rather than stated: the agent can infer this is the tool for checking whether features like email or errors are enabled on a branch. There is no explicit when-to-use, no when-not, and no pointer to addon.status or capabilities.add as alternatives, which is a real gap given how many similarly named siblings exist.

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