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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint, so the description is not burdened with safety claims. It adds context about the time-series window behavior ('supports resolution and quantity to control the time-series window'), which is helpful. However, it does not discuss potential errors, rate limits, or response format beyond what the output schema provides.

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 a single, front-loaded sentence that states the main purpose first and then adds the optional parameter behavior. Every word earns its place, and it avoids unnecessary detail.

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?

Given the tool's simplicity, an output schema exists, and annotations cover safety, the description is reasonably complete. It explains the key parameters and the time-series nature, which is the main functional nuance. The only gap is the ambiguity around 'resolution' caused by the conflicting schema example, but the description itself is sufficient for a competent agent to infer behavior.

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%, so the description must compensate. It explains that 'quantity' is a 1-30 range and 'resolution' relates to time granularity ('days'), adding meaning beyond the bare property names. However, the schema example shows resolution as '1920x1080', which is an image resolution, creating confusion and reducing clarity. The description is not sufficient to fully resolve parameter semantics.

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 clearly states the action ('Fetch'), the resource ('view, download, and like statistics for a single Unsplash photo'), and the scope ('by id'). This distinguishes it from siblings like 'photo', 'photo_download', and 'list_photos', which handle other aspects of photos.

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?

The description implies the tool should be used when retrieving stats for a single photo, and mentions the ability to control the time-series window with resolution and quantity. It does not explicitly exclude alternatives or state when not to use it, but the context is clear enough for a focused tool.

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