SHA-256 of a file

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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so safety is fully covered. The description adds only the intended use (recording exact output) and says nothing about error behavior, hashing of missing/unreadable files, or digest encoding.

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?

One short sentence, front-loaded with the operation and result. Nothing is wasted, though it is arguably over-compressed for the amount of unstated context.

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 rich annotations and an output schema present, the definition is close to sufficient, but the meaning of 'path' — the only input — is left entirely unstated, which is the one thing an agent must get right to invoke it.

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 single parameter 'path' has 0% schema description coverage and the description adds no meaning: it does not state whether the path is absolute or relative, local-only, or what file types are accepted (the tool name suggests PDF, the description says 'a file').

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: returns the SHA-256 digest of a file. The purpose is unambiguous and clearly disjoint from the pdf_form_* siblings, though it never explicitly contrasts itself with them.

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 clause 'so the exact output can be recorded' implies an integrity/audit use case, but there is no explicit guidance on when to call this versus other verification steps, no prerequisites, and no exclusions.

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