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

readOnlyHint=true already establishes the safe-read profile, so the description's job is to add more, and it does: it discloses that the response is expanded with the request's message thread and associated user records, which the agent would not know from annotations or schema. It still omits any rate-limit, permission, or not-found behavior.

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?

Two short sentences, front-loaded with the purpose and the expanded-return note. The trailing 'When I Work: GET /2/requests/{request_id}' mapping is mildly redundant for an agent but harmless and compact, keeping the whole thing tight.

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 one-parameter read with no output schema, the description covers what the agent most needs to know: that it fetches a single request and that the payload includes the message thread and users. Remaining gaps (error/empty behavior) are minor at this complexity level.

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 the single parameter request_id is fully documented there, so the baseline is 3. The description's 'by id' adds no format, range, or source detail beyond what the schema already supplies.

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?

States a specific verb (Fetch) and resource (one time-off request by id), and the singular 'one ... by id' clearly distinguishes it from the sibling wheniwork_list_time_off_requests. It also names the expanded content (message thread and users), so an agent knows what this returns versus the list variant.

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?

Usage is only implied: 'by id' signals this is the retrieval-by-identifier path, distinct from the list tool, but there is no explicit when-to-use statement, no prerequisite (e.g. how to obtain a request_id), and no mention of the update/create siblings. Adequate but with clear gaps.

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