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

The description complements the annotations (readOnlyHint, idempotentHint) by adding useful behavioral context: it returns the detected format and supported status, and importantly notes 'No payment required.' It does not contradict the annotations and provides transparency beyond the structured data.

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 three concise sentences, each contributing value: what it does, what it returns, and when to use it. No wasted words; the privacy policy link is supplementary and doesn't detract.

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 detection tool with one well-documented parameter, annotations, and sibling context, the description covers the essential behavior, return value, and use case. It is fully adequate for an agent to select and invoke the tool correctly.

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 already provides a complete description for the single filename parameter ('Filename or URL to check. The format is detected from the file extension.'). The description repeats this idea without adding extra syntax or format details, so it meets the baseline for high schema coverage.

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 'Detect' and names the resource 'geometry file format from a filename or URL.' It clearly distinguishes itself from sibling format tools by focusing on pre-analysis format checking rather than conversion or processing.

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 explicitly states when to use the tool: 'Use this to check format support before making a paid analysis call.' It provides clear context but does not explicitly mention when not to use it or name alternative tools.

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