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

Beyond the annotations, it discloses several non-obvious traits: output is a new hosted image, existing posts are untouched (reinforcing destructiveHint=false), edits count against the image allowance by model cost, and failed edits are refunded. These billing and non-destructive guarantees are exactly the context annotations cannot express.

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?

Four short sentences, front-loaded with the core action and free of filler. Minor redundancy: the first line 'Edit an image' merely repeats the title annotation, but the rest of the content earns its place.

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 mutation tool with no output schema, the description covers the essential behavior: source constraint, return value ('new hosted image'), and cost/refund semantics. The remaining gap is parameter documentation, but the overall picture is sufficient to invoke 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 0% for all three parameters (model, prompt, imageUrls). The description offers only indirect hints ('media library' for imageUrls, 'model cost' for model) and says nothing about the prompt's role, limits, or the multi-image array. It fails to compensate for the coverage gap.

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 specific verb and resource ('Edit an image') and clarifies it operates on uploaded images via a prompt. It is clearer than a bare name, but it never distinguishes itself from the sibling 'customEdit' nor from 'generateImage', leaving some ambiguity about which editing tool to pick.

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 supplies one real prerequisite ('Source images must be in your PostQuickAI media library'), which is useful. However, there is no explicit when-to-use vs when-not-to-use guidance and no routing to alternatives such as 'generateImage' for new images or 'customEdit', so usage is only implied.

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