What got done (today / this week / any window)

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

Annotations already establish readOnlyHint=true and idempotentHint=true, so the safety profile is covered. The description adds the behavioral frame the annotations cannot: the report is derived 'from the log' and is a composite of enumerated categories, which effectively serves as a proxy for the return shape given there is no output schema.

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 plus one short directive, front-loaded with the outcome and scope before the format guidance. Every clause carries information — the enumeration, the format rationale, and the period preference — with no filler.

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 compensates by enumerating the report's sections, and with annotations covering safety and 100% schema coverage covering parameters, little is left unexplained. An agent has enough to call it and to anticipate what comes back.

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 baseline is 3, but the description genuinely adds meaning beyond the schema: it explains why to pick 'markdown' vs 'json' and notes a preference for named periods over 'all'. It does not, however, clarify the from/to override relationship with period or the project scoping.

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 ('activity report' over a window) and enumerates exactly what it aggregates — tasks completed/opened, time in 'doing', lead time, models, decisions, dead ends, open questions. That content list distinguishes it from siblings like list_tasks or search, which return raw items rather than an aggregated log summary, though it never names a sibling explicitly.

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 gives real selection guidance: format 'markdown' 'to hand on' vs 'json' 'to reason over', plus 'Prefer a named period to all'. These are clear conditions for choosing among options, but there is no when-to-use-this-instead-of-alternatives statement (e.g., vs list_tasks/search) and no exclusions.

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