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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so safety is fully covered. The description adds nothing behavioral beyond annotations (no auth, rate limit, or not-found behavior); the only extra is the raw HTTP path, which is structural rather than behavioral.

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, front-loaded sentences with no filler. The route template is mildly redundant with the schema but useful for cross-referencing the underlying API, so it earns most of 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 read-only single-record get this is mostly adequate, and annotations cover the safety profile. However, with no output schema, the description never hints at what a timesheet line contains or what a missing id returns, leaving a real gap for an agent consuming the result.

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%, with both parameters documented as originating from keypay_list_businesses and keypay_list_timesheets. The description's route template restates the two id slots but adds no format or constraint detail beyond the schema, so the baseline 3 applies.

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 and resource ('One timesheet line by id') and pins down the exact REST route. An agent can tell this retrieves a single timesheet line rather than a collection, though it never names keypay_list_timesheets as the counterpart.

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 'by id' phrasing implies this is the single-record lookup versus the list sibling, but there is no explicit when-to-use statement or condition that selects this over keypay_list_timesheets. Usage is only inferable.

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