Download file

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

Beyond the readOnlyHint and openWorldHint annotations, the description discloses that the URL is short-lived, grants read access to one object only, is time-limited, and returns the URL rather than the file bytes. This adds valuable behavioral context that the annotations do not cover.

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 two sentences, front-loaded with the primary action, and each sentence earns its place: the first states purpose and requirement, the second explains behavior and return value. No wasted words.

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 URL-returning tool, the description fully covers what it does, what it requires, what it returns, and the key behavioral nuance (does not load bytes). With readOnlyHint and detailed schema, no essential context is missing.

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 has 100% description coverage for all parameters, so the schema already explains filePath, storageId, bucketName, and forceDownload. The description adds no parameter-level meaning beyond stating that bucketName is required, which is already in the schema. Baseline 3 is appropriate.

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 opens with a specific verb and resource: 'Get a short-lived pre-signed download URL for a file.' It clearly states the action and result, and distinguishes itself from siblings by noting it does not load file bytes into the conversation, differentiating from upload or content-fetching tools.

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 provides context (requires bucketName, URL is time-limited, share with care) but does not explicitly mention when to use this tool versus alternatives like share_link, nor does it state exclusion conditions beyond not loading bytes. The 'does not load file bytes' is more a behavioral fact than a usage guideline.

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