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

With no annotations, the description carries the behavioral disclosure burden, and it does so well: it reveals sort order, inclusion of running timer and customer totals, exact semantics of 'unbilled' and 'billed', ISO 8601 format, and default 30-day range. It stops short of describing the response envelope, but the stated behavior is unusually concrete for a list tool.

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 the core behavior first and optional filters second. Every phrase adds information, with no filler or repetition of schema boilerplate.

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 listing tool with no required parameters and no output schema, the description is nearly complete: it covers ordering, filters, status semantics, date format, and default range. Remaining gaps such as response item shape are minor and partly covered by the parameter schema.

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 the baseline is 3; the description adds real value on top by explaining the status taxonomy ('billable, stopped, not on a live invoice'), how dealId fills in contact/company, and the default 30-day summary. This goes beyond field-name documentation.

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 opens with a specific verb and resource: 'List time entries, newest first' and further specifies it includes the running timer and totals by customer. This clearly distinguishes it from write/timer siblings such as time_log, time_timer_start, and time_timer_stop.

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 description gives strong contextual guidance: it is for reading/filtering time entries, optionally by deal/company/contact or billing status, with a default 30-day summary range. It does not explicitly name when-not-to-use alternatives, but the read-vs-write contrast with sibling tools makes the intended use clear.

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