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

Annotations already declare readOnlyHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds useful context beyond that — that entries link to the invoice that billed them and how billing status drives filtering — but says nothing about pagination defaults, volume, or result ordering that would matter when pulling large activity sets.

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 sentences, both load-bearing: the first establishes the record type and returned fields, the second enumerates filters. It is dense but front-loaded and free of filler, though the parenthetical '(needs company)' is slightly terse.

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?

With no output schema, the description usefully compensates by listing the fields each activity carries (project, employee, times, breaks, description, billing invoice). Combined with a fully documented schema and read-only annotations, an agent has enough to call it correctly; only pagination and result-ordering expectations are unaddressed.

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 all nine parameters are already documented in the schema, including the employee_no/company_no dependency and the billable_only customer-project nuance. The description only restates the filter set at a coarser level, adding no syntax or edge-case detail beyond the schema.

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 names the resource precisely (recorded time-tracking activities, record ACTIVITIES_GET) and enumerates the returned fields, so an agent knows this is a read of time entries rather than projects or invoices. It stops short of explicitly saying 'list' or contrasting with sibling list tools such as collmex_list_projects.

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?

Usage is only implied through the filter list ('Filter by project, employee (needs company), date range, only not-yet-billed...'), which hints at retrieval scenarios but never states when to prefer this tool over collmex_list_projects or collmex_list_invoices. The note that employee filtering requires a company is a real prerequisite, but no exclusions or alternatives are given.

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