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

Annotations only give the generic safety profile (readOnly=false, destructive=false). The description adds the crucial behavioral fact that it 'Creates a DRAFT only — nothing on Google changes,' plus the human-confirmation requirement before publish_change. This is high-value context that the annotations cannot convey.

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 tight sentences, front-loaded with purpose, then the alternative, then the draft/confirmation semantics. No filler; every clause adds actionable 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?

No output schema exists, and the description still signals that a draft is returned and instructs the agent to surface it verbatim. For a 2-param draft tool, the purpose, alternative, and follow-up workflow are all covered.

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?

With 0% schema coverage the description must carry parameter meaning: it fully lists the category enum and adds real constraints for image_url ('public https link to a JPEG, PNG or WebP') that the schema lacks. The category list, however, merely restates the enum without explaining what each value denotes.

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+resource (draft adding a photo), enumerates the valid categories, and constrains the source (a public https link to JPEG/PNG/WebP). It also names the sibling it is not (upload_photo), so an agent can distinguish it without opening either schema.

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 routes the alternative case: 'For a photo on the owner's phone or computer, use upload_photo instead,' and prescribes the full workflow (show the draft word-for-word, then publish_change only after the owner says yes). When-to-use, when-not, and the confirming step are all stated.

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