Get correspondent

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

Annotations already disclose that the tool is read-only, idempotent, and non-destructive, so the description does not need to cover safety. The description adds that the response includes all fields of the correspondent, which is useful, but it does not mention what happens if the ID does not exist or how errors are surfaced. For a simple getter with a strong annotation profile, this is acceptable but not fully transparent.

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 one clear sentence with no redundancies or filler. 'Fetch a single correspondent by ID' is front-loaded, and 'with all fields' adds meaningful return-value information. Every part 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?

For a tool with one parameter, no output schema, and no nested objects, the description is mostly complete: it identifies the resource, the lookup key, and the return scope ('all fields'). The only notable omission is behavior for a non-existent ID, such as a 404 vs a null result. Given the low complexity, this is a minor gap.

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 has a single required `id` integer with bounds but no property description, and schema description coverage is 0%. The description's 'by ID' matches the parameter name and clarifies that the integer is the correspondent identifier, but it adds no further semantics such as where the ID comes from or what formats are valid. This is the minimum compensation for the missing schema coverage.

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 says 'Fetch a single correspondent by ID, with all fields,' which names a specific verb, a specific resource, and a precise selection criterion. This clearly distinguishes it from list_correspondents, which would return multiple correspondents, and from create/update/delete mutations of correspondents. An agent can confidently tell what this tool does without opening the 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?

The description implies the use case: when you already have a single correspondent ID and need the full corresponding record. However, it does not explicitly say to prefer this over list_correspondents when only one ID is needed, nor does it describe how to obtain the ID. The guidance is implied rather than stated.

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