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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so safety is covered. The description adds genuine context beyond that: the corpus_lag_note snapshot-cutoff semantics that explain absence-vs-nonexistence, and the constraint that no caller paths or external URLs are accepted. Return details are covered by the output schema, so nothing further is required.

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?

Three sentences, front-loaded with the usage trigger before the purpose statement, and each sentence carries distinct information. Slightly dense in the opening clause about corpus_lag_note, but no filler.

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?

Complete for a no-param status tool: purpose, trigger conditions, the interpretation caveat for missing grants, and input constraints are all covered. With annotations and an output schema present, no further behavioral disclosure is needed.

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?

Zero parameters, so the baseline is 4. The description usefully confirms this by stating it takes no parameters and accepts no caller paths or external URLs, matching additionalProperties=false in the schema.

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 states a specific verb and resource: 'Read-only status for the deployed NIH project corpus and official sidecars.' It also enumerates what status means (whether corpus is loaded, which sidecars exist, staleness), clearly distinguishing it from query siblings like search_grants or fetch.

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 explicit trigger conditions ('when the user asks whether the OpenNIH corpus is loaded, which official sidecars are available, or how stale the data might be') plus a precondition for use before reporting 'no such grant'. The negative case — grant absent because it postdates the snapshot cutoff — is spelled out rather than left to inference.

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