contacts_get_photo

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It merely states 'Get the photo URL' without detailing return behavior (e.g., whether URL can be null), error conditions, or side effects. It adds little beyond what the tool name already implies.

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 concise sentence with no redundant words, appropriately sized for a simple getter tool. It earns its place by clearly conveying the primary function.

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 lack of parameter semantics, behavioral details, and annotations, the description is incomplete even for a simple tool. A user cannot determine how to construct resource_name or what to expect as a response. The presence of an output schema (not shown) might mitigate, but the description itself leaves significant gaps.

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 input schema has a single required parameter resource_name with no description (schema coverage 0%). The description mentions 'for a contact' which gives a vague hint that resource_name identifies the contact, but it does not explain the expected format (e.g., 'people/123') or provide any additional semantic detail.

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 'Get the photo URL for a contact' clearly states the action and resource, making the tool's purpose straightforward and distinct from sibling tools that handle other contact operations. It does not explicitly differentiate from alternatives, but no similar photo-related tool exists among siblings.

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?

No explicit usage guidance or alternative tools are mentioned, but the description implies this tool is used when you need a contact's photo URL. The context of the tool name and description provides a basic sense of when to use it, but no explicit when/why or exclusions.

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