firestarter_upload_image

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

Annotations only indicate that this is not read-only and not destructive, so the description carries the behavioral burden. It does so well by explaining server-side fetching and re-hosting, the 6 MB limit, the return of a permanent URL, and the known failure mode of download-and-rebase.

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 dense but every sentence earns its place: purpose and output, input-form alternates, decision rule, and failure mode. It is front-loaded with the most important information and contains no 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 tool with no output schema, the description supplies the needed expectation of the returned hosted URL, input requirements, constraints, and a known pitfall. That is sufficient for an agent to invoke it and interpret the result.

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 covers all three parameters at 100% coverage, so the baseline is 3. The description adds value beyond the schema by framing image_url as the preferred form, image_base64 as the fallback, and explaining the real-world tradeoff, which helps the agent decide between them correctly.

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 opening sentence states a specific verb and resource ('upload a product photo') and the concrete outcome ('get back a permanent public URL'). It also identifies downstream consumers (firestarter_list and firestarter_update_listing), which clearly distinguishes this tool's role among the many firestarter siblings.

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 tells the agent when to use image_url versus image_base64: use image_url whenever a URL exists, and fall back to image_base64 only when no URL exists. It even explains why image_url is the reliable form by naming the known failure mode it avoids.

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