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

Annotations already declare readOnlyHint=true, so the tool's safety profile is clear. The description adds useful behavioral context beyond the annotations by specifying the exact output facets the analysis returns (type, encoding, size, MIME type, magic bytes, structure summary). It does not disclose limitations like file size limits, but the low-risk read-only nature makes that acceptable.

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 one front-loaded sentence that immediately states the action and the return values. The 'File Analyzer —' prefix redundantly repeats the tool name and the '[category: analyze]' tag adds marginal value, but there is no meaningful padding or wasted prose.

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 one-parameter read-only tool with no output schema, the description covers the essential information: what the tool does and what it returns. The lack of explicit guidance about specialized sibling tools is a gap, but the low complexity and full schema coverage keep the definition reasonably complete.

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 has 100% description coverage: the single binary 'file' parameter is documented as 'Input file (any)'. The description adds no extra parameter-level details, so the baseline score of 3 is appropriate since the schema fully handles parameter semantics.

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 uses a specific verb ('Analyse') and names the resource ('a file') while enumerating concrete outputs: type, encoding, size, MIME type, magic bytes, and structure summary. However, it does not explicitly distinguish itself from specialized sibling analyzers such as analyze_metadata or analyze_encoding_detector, leaving some ambiguity about which tool to choose for a generic file.

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 generic phrasing 'Analyse a file' and the '[category: analyze]' tag imply this is a general-purpose analyzer, but there is no explicit statement about when to use it instead of specialized tools like analyze_audio, analyze_csv, or analyze_pdf_inspector. No alternatives or exclusions are mentioned, so the agent must infer usage context.

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