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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds valuable behavioral context beyond annotations: it generates a presigned download URL, the URL is valid for 1 hour, and it only fetches existing media. No contradiction with 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?

Every sentence earns its place: first sentence states what it does, second clarifies limitations and names an alternative, third gives a critical detail (URL expiry). No filler, well front-loaded.

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 tool with one parameter, rich annotations, and no output schema, the description is complete. It covers the purpose, key side effects (presigned URL, expiration), and what it does not do. No important gaps remain.

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 input schema fully describes the single parameter (mediaId) with a clear description, and schema coverage is 100%. The description reinforces the meaning by saying 'identified by mediaId' but provides no additional detail beyond the schema baseline.

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?

Uses a specific verb ('Retrieve') and clearly identifies the resource ('original source media file of an already-analyzed job' generated via presigned URL). It explicitly distinguishes itself from sibling tools by stating it does not upload or start analysis, and even names the alternative tool (echosaw_analyze_media_url).

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?

Provides explicit when-to-use guidance: for already-analyzed jobs and fetching existing media only. Clearly states what it does not do (upload or analyze) and names the alternative for those cases. This fully addresses when to choose this tool over siblings.

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