Get a link to the PDF

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

Annotations only say readOnlyHint=true and openWorldHint=false; the description goes well beyond by disclosing the 15-minute expiry, the signed-link nature, the exact response shape, why pdfStale is always false, and the staleness caveat that the link excludes edits made since that typeset. That is precisely the staleness semantics an agent could otherwise get wrong.

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 purpose and trigger, then return shape, then caveats — good ordering with no filler. The 'pdfStale is always false here because the link is to that file, whichever typeset wrote it (by you or by a person)' clause is dense and slightly convoluted, keeping it short of a 5.

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?

No output schema exists, yet the description enumerates the returned fields {pdfUrl, pdfFile, pages, typesetAt, deepLink} and explains the staleness semantics, plus the prerequisites (compile first). Nothing an agent needs to call this correctly is missing.

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 coverage is 100%, so `branch` and `project` are already fully documented in the schema, including the echo of {branch, head}. The description only refers to 'the PDF on disk for the branch' and adds no syntax or defaulting detail beyond that schema text, so the baseline 3 applies.

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 and resource ('a fresh signed link to the PDF on disk for the branch, without recompiling') and immediately contrasts it with recompiling, separating it from the `compile` sibling. An agent can tell exactly what this returns.

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 explicit trigger conditions ('when a compile result's pdfUrl has expired (15 minutes) or the user asks to see the PDF again') and explicit exclusions with the alternative named ('if you have written on this branch since your last compile result, call compile instead'). It even handles the no-output case: 'No output yet → compile first.'

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