upload_skill_image

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

Annotations already declare this is not read-only, is open-world and non-idempotent; the description adds meaningful context beyond them: 'No generation is started' (scoping the side effect) and a hard rule against fabricating base64 or attachment paths. It does not describe auth, rate limits, or what happens on repeat uploads.

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?

Three short sentences, front-loaded with the outcome (return imageUrl), followed by constraints. No filler or redundancy.

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 3-parameter, no-output-schema prep tool with annotations covering the safety profile, the description covers the outcome, the no-generation caveat, and the input-integrity rule. It could say more about what a prepared image is used for next, but nothing critical 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?

Schema description coverage is 100%, so the enum purpose values, sourceUrl vs imageBase64 choice and size limits are already documented. The description only re-emphasizes 'actual accessible bytes/URLs' and the URL-or-path distinction, adding little beyond 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?

States a concrete action (prepare a reference image) and its result (return imageUrl), which an agent can distinguish from the generate_*/upscale_image siblings. The verb 'prepare' vs the tool name 'upload' is slightly loose, but intent is clear.

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?

It hints that URLs and local paths may bypass this tool and go straight into a generation skill's image field, but it never states cleanly when to call upload_skill_image versus passing a URL directly. Usage is implied rather than prescribed.

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