upload_image_from_url

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

With no annotations provided, the description carries full responsibility and does an excellent job disclosing behavioral traits: SSRF guard restrictions, source limitations (public http(s) only, rejects private/localhost and oversized responses), and the upload-to-Ghost hosting behavior. No contradictions.

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 consists of two focused sentences: the first states the core action, and the second adds essential constraints. It is front-loaded and contains no extraneous information.

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?

Given the tool's simplicity, an output schema exists (returning the URL), so the description does not need to cover return values. It fully covers fetching, constraints, and hosting behavior, making it complete for an agent to select and invoke the tool correctly.

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 description coverage is 100%, so the baseline is 3. The description adds no additional meaning beyond the schema for 'source_url' and does not mention the 'purpose' parameter. Thus, it provides no extra value over the input 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 action: 'Fetch a public image by URL and re-upload it to the blog, returning the URL.' The verb 'fetch' and 're-upload' combined with the resource 'image' make the purpose unambiguous. It distinguishes itself from sibling tools like 'upload_image' by explicitly mentioning fetching from a 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?

The description provides clear context on when to use the tool: when you have a public image URL and want to host it on the blog. It also lists constraints (SSRF guard, public http(s) only, no private/localhost, oversized responses refused). However, it does not explicitly state when not to use it or mention alternatives like 'upload_image' for local files.

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