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

Annotations already declare readOnly, idempotent, closed-world and non-destructive, so the safety profile is covered. The description adds genuine value beyond that: ordering ('newest first'), an accompanying total hours, and the Free-tier 7-day window with explicit notice. It omits pagination behaviour beyond limit and any indication of row-count ceilings or response size.

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 dense sentences with no filler; the output shape comes first, then the ordering and total, then the tier constraint. Every clause carries information an agent would otherwise have to guess.

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?

There is no output schema, and the description compensates by enumerating the returned columns, the row ordering, and the aggregate total. Combined with the fully covered input schema and safety annotations, an agent has everything needed to call this correctly and interpret 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%, so to/from/limit/project are all documented in the schema, including the default of 50. The description reinforces ordering ('newest first') and date scoping but adds no syntax, format, or interaction detail beyond what the schema already supplies, making the baseline 3 appropriate.

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 gives a specific verb ('List'), a specific resource ('logged entries'), and even the exact return shape (id, day, start, project, task, hours, billable, tags, note). That column list implicitly separates it from summary_day/summary_week/report siblings, which aggregate rather than list raw rows.

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?

It states a real usage constraint – Free reads only the last 7 days and announces that – which tells the agent a request may be truncated. It never names an alternative tool (e.g. summary_day or report) or says when a listing beats an aggregation, so selection guidance is only implied.

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