s3_generate_presigned_url

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It explicitly warns that the URL is a bearer secret and that anyone possessing it can download the object until expiry, plus it mandates user confirmation and flags the tool as dangerous. This goes beyond basic purpose and addresses key security implications.

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 compact, front-loaded with the primary purpose, and every sentence provides distinct value: the function, the security warning, and the usage restriction. There is no redundant or filler content.

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 tool with 5 parameters, no output schema, and no annotations, the description covers the essential aspects: purpose, security, and when to use. It doesn't describe the return value (a URL) explicitly, but that is implied by the tool name. Minor gaps like error conditions are not critical for this type of tool.

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?

Schema coverage is 100%, so the baseline is 3. The description adds no additional parameter semantics beyond what the schema already provides for bucket, key, region, provider, and expires_in. It doesn't mention defaults, constraints, or provider-specific nuances that aren't already in the schema.

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 clearly states the tool generates a time-limited pre-signed URL for read access to an S3 object, using a specific verb and resource. It distinguishes itself from sibling S3 tools like s3_download_object or s3_upload_object by focusing on URL generation rather than direct data transfer.

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 clear usage context: it is 'reserved for dangerous guard mode' and requires user confirmation before calling. While it doesn't name explicit alternatives or when-not-to-use scenarios, the safety warning and guard mode restriction effectively guide appropriate use.

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