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

Despite annotations already declaring idempotentHint=false and openWorldHint=true, the description adds valuable context: each call costs generation credits, takes longer than other tools, requires an API key, the resulting URL is public and cannot be deleted, and results vary between runs. This goes well beyond structured fields.

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 front-loaded with the core action and organized into three short paragraphs. Every sentence serves a purpose—no fluff or repetition. Slightly longer than strictly necessary but well-structured.

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 moderate complexity (generation, upload, return URL), the description covers the return value, non-idempotence, cost, deletion constraints, and variability. It omits error conditions or rate limits, but those aren't critical given the schema and annotations. Overall, quite complete.

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 schema fully describes both parameters. The description adds minor extra guidance (e.g., 'avoid asking for text in the image') but does not significantly enhance meaning beyond what's already present. Baseline 3 is appropriate.

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 states a specific verb+resource: 'Generate an image from a text prompt with AI, upload it to the Misar.Blog CDN, and return its public URL for use as cover_image_url when publishing.' It clearly differentiates from siblings by mentioning 'use upload_image for a file the user already has.' No ambiguity.

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?

Explicitly provides when to use and when not: 'Use it when no artwork exists yet; use upload_image for a file the user already has.' Also warns about non-idempotence and cost, which informs decision-making. This is exemplary guidance.

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