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

Annotations already declare readOnlyHint=false, destructiveHint=false, openWorldHint=true and idempotentHint=false; the description reinforces the write nature and adds the non-obvious referential constraint that projectId must match the task's project. It stops short of warning that retries will create duplicate entries, which the non-idempotent hint implies.

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 terse sentences, front-loaded with the WRITE marker and the resource, then the constraint, then the unit, then the endpoint. No filler sentence.

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 six-required-parameter mutation with no output schema, the definition covers the main failure mode (wrong projectId) and unit confusion. It omits whether startedAt/stoppedAt must be internally consistent with the time value, which would be a useful completeness addition.

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 coverage is 100%, so baseline is 3; the description goes beyond it by disambiguating the unit ('time is the length in seconds, 5400 = 1.5 hours') with a concrete conversion example and by flagging the cross-parameter constraint tying projectId to taskId. It says nothing about startedAt/stoppedAt relationship to time, leaving a small gap.

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 ('record a time entry against a task') and prefixes it with 'WRITE:', making the mutation nature and the object unambiguous. An agent can immediately distinguish it from the read-only siblings like plutio_list_time_entries.

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?

Gives a concrete precondition — read the task first, and use that task's own projectId — which steers the agent to a preceding lookup call. It does not explicitly name the sibling to read from or describe when not to use it, but the guidance is actionable.

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