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

The readOnlyHint=true annotation already signals a safe read operation. The description adds the HTTP method (GET) but does not provide further behavioral context such as error handling, rate limits, or how fetch_contact affects the response. No contradiction with annotations.

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 two short sentences with no filler. The purpose is front-loaded, and the REST endpoint is a useful extra detail. Every word 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?

This is a simple get-by-id tool with only two parameters, both documented in the schema. The description is sufficient for the agent to invoke the tool, though it does not mention that fetch_contact alters the response shape. Given no output schema, some ambiguity remains about the return format, but the tool is simple enough that this is acceptable.

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 100%, and both 'id' and 'fetch_contact' have clear descriptions in the schema. The description only mentions 'id' implicitly and does not add additional meaning beyond the schema, so the baseline of 3 is appropriate.

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 ('Get'), the resource ('a single call'), and the identifier ('by id'), and it also mentions the REST endpoint. This distinguishes it from sibling tools like list_calls or search_calls, which have different scopes.

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 this tool should be used when you have a specific call id and need its details, but it does not explicitly mention when not to use it or recommend alternatives like list_calls or search_calls. There is no exclusions or comparative guidance.

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