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

Annotations already cover read-only, idempotent, non-destructive semantics, so the description correctly spends its words elsewhere — adding the plan-level 'Agents' permission requirement, which is a real call-time prerequisite an agent cannot infer from annotations. It stops short of noting time windowing or freshness of the totals.

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 short sentences, front-loaded with what is returned, then the scope constraint, then the alternative and the prerequisite. No redundant restatement of the title or annotations.

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 does the essential work of enumerating the returned metrics and clarifying aggregation scope, and adds the permission requirement. It does not state the reporting period for the totals, which is the one thing an agent might still need to assume.

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?

The tool takes zero parameters, so there is no parameter semantics to explain; the baseline for a no-param tool applies. The description instead clarifies the implicit scoping decision (all agents, no filter) that an agent might otherwise expect to control.

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?

Names the exact metrics returned (conversations handled, replies sent, appointments booked) and the aggregation scope (all agents). A reader knows precisely what this tool produces and how it differs from agent_logs without opening any schema.

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?

Explicitly routes the agent: use this for aggregate totals, and read `agent_logs` for a single agent's quality. It also pre-empts a likely misuse by stating 'there is no per-agent breakdown here.'

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