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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered. The description adds value beyond them by disclosing the return shape (one row per agent id) and the units of the time fields, plus the workflow dependency on list_agents for naming.

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, front-loaded with the resource and window, then the metric list and keying/naming detail. No filler and nothing repeated from the 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 responsibly names the returned metrics, their units, and the row key, and the parameters are fully covered by the schema. It omits edge cases such as whether agents with no conversations appear as zero rows, which keeps it just short of fully complete.

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%; the days and fields parameters are fully documented in the schema, including the 'today included' counting rule and the default of 30. The description contributes only the N-days framing and does not restate the field enum or default, so the schema does the heavy lifting.

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?

States a specific verb+resource with scope: per-agent performance over the last N days, enumerating the exact metrics (conversations handled, avg resolution, first response, reply times). The 'per-agent' framing plus the 'rows are keyed by agent id' note separates it from team/conversation/sentiment report siblings without needing to name them.

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 time window ('last N days') and the per-agent granularity give clear context for when this report applies, and it routes the agent to list_agents to resolve agent ids. It stops short of explicit exclusions (e.g., 'for team-level rollups use get_team_report'), so it is clear context rather than full when/when-not guidance.

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