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

The annotations already provide readOnlyHint=true, idempotentHint=true, openWorldHint=false, and destructiveHint=false. The description adds a specific behavioral trait beyond that: an unknown id yields a 'typed miss with no document fields', which informs the agent about failure semantics. This is useful context not covered by the annotations.

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?

The description is a single, tight sentence with no superfluous words. It front-loads the core action ('Fetch one public corpus document by id') and appends a concise edge-case detail. This is appropriately sized for a simple one-parameter tool.

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 simple read tool with a single parameter and no output schema, the description covers the essential context: what the tool fetches, its public scope, and the failure behavior for unknown ids. It does not describe the shape of the returned document, but given there is no output schema and the tool is straightforward, this is a minor gap.

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 exposes a single required string parameter 'id' with no description (0% schema coverage). The description only says 'by id', which essentially restates the parameter name and tool name. It does not explain id format, length, expected values, or any validity constraints—so the agent gets no real guidance beyond the obvious.

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 ('Fetch'), a specific resource ('one public corpus document'), and the retrieval key ('by id'). It also clarifies the scope with 'public corpus', which implicitly distinguishes it from the sibling search_school. The unknown-id detail adds specificity without blurring the core purpose.

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?

The description does not mention when to use this tool versus the sibling search_school or when not to. There is no explicit routing guidance, no mention of alternatives, and no exclusions. The agent must infer that fetch-by-id is for direct lookups, while search is for queries—but this is not stated.

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