get_image_by_hash

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

Annotations are absent, so the description carries full burden. It adds behavioral context like optional access_token with 'will use cached token if not provided' and implies read-only via 'get, download, visualize.' However, it does not explicitly state that it is read-only, nor does it disclose potential failure modes, rate limits, or required permissions. This is a moderate omission.

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 efficiently structured in three sections: purpose, usage guidance, and args/returns. Every sentence earns its place—there is no fluff, and the key information is front-loaded. The clear organization makes it easy for an agent to parse quickly.

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 simple tool with no annotations and no output schema, the description covers purpose, usage, parameters, and return value. The return statement 'The image ready for direct visual analysis' gives a general idea but could be more explicit about the format (e.g., URL, binary data). Still, given the tool's simplicity, this is near-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?

The schema provides only titles and types, with 0% description coverage. The description's Args section compensates well: it explains the accepted formats for account_id ('act_XXXXXXXXX or bare numeric'), the purpose of image_hash, and the optionality of access_token with caching behavior. This adds meaningful semantics beyond the schema, though the image_hash description could be more detailed.

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 opens with a clear verb+resource: 'Get, download, and visualize a Meta ad image by its hash.' It also explicitly distinguishes from the sibling tool by stating 'To view the image of an existing ad, prefer get_ad_image(ad_id),' which removes ambiguity about when this tool is appropriate.

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 gives explicit usage context: 'Use this when you have an image_hash without an ad' and provides concrete examples of how such hashes arise. It also clearly states an alternative tool for a different scenario, satisfying both 'when to use' and 'when not to use' guidance.

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