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

The description discloses that the tool does not actually upload the files itself but returns pre-signed URLs, and that the agent must PUT to those URLs and then call verify_photo with the returned object keys. This adds meaningful behavioral context beyond the sparse annotations, though it does not mention URL expiration or upload completion details.

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 compact sentences that front-load the core function and immediately follow with actionable steps. Every sentence contributes essential information with no redundancy or filler.

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 zero-parameter tool with an output schema, the description fully covers the workflow: obtaining URLs, uploading files, and completing verification with the returned keys. Nothing critical is missing for correct invocation and follow-through.

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 zero parameters and schema description coverage is 100%, so there are no parameter semantics to describe. Per the baseline for zero-parameter tools, this is effectively handled; the description focuses on the workflow and response usage instead.

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's purpose: obtaining pre-signed S3 PUT URLs for uploading large RAW and JPEG files. It distinguishes itself from verify_photo by explaining that it handles the upload mechanism rather than inline bytes, making the resource and action unambiguous.

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 explains when to use this tool — for large files where inlining bytes would hit request-size limits — and outlines the next required step of calling verify_photo afterward. It does not explicitly name alternatives or state when not to use it, but the context is clear enough for an agent to follow the intended flow.

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