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

Annotations only declare destructiveHint=true; the description adds real signal by flagging this as a WRITE that is non-idempotent (a new entry per call, duplicates likely on retry). That is meaningful beyond the annotation. It still omits what is returned (entry id?) and whether any validation like end>start is enforced server-side.

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?

Three short sentences, front-loaded with the WRITE marker and the duplicate-entry warning. The trailing endpoint string is mostly provenance metadata rather than agent-facing guidance, which is the only mild waste.

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 7-parameter, 6-required mutation with no output schema and low param description coverage, the definition covers the essential create semantics but leaves gaps: return value, required field formats not in the schema, and no note on duplicate/overlap handling beyond 'do not repeat it'.

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 only 43% — user_id, notes, start_time and end_time carry no descriptions, only types and a datetime regex. The description says nothing about parameters; 'for a user' and 'finished' only faintly gesture at user_id and the start/end pair, so the coverage gap is not compensated.

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 ('add a finished time entry for a user') and the qualifier 'finished' implicitly separates it from timetac_start_time_tracking / timetac_stop_time_tracking, which handle running timers. It also names the underlying endpoint. It does not explicitly name the sibling it replaces, keeping it just below the top mark.

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?

'Each call creates a new entry, so do not repeat it' gives a useful caution about retries, but there is no explicit statement of when to choose this over timetac_start_time_tracking, timetac_stop_time_trackings, or the list tools, and no prerequisites (permissions, whether the task/user must already exist).

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