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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so safety is covered. The description does add real value beyond them: it discloses the required account-bound computer:write OAuth scope and that local owner approval may be prompted, which an agent cannot infer from structured fields. It omits what 'recent' means (time window) and any rate-limit or result-size behavior.

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, each earning its place: purpose first, sibling differentiation second, prerequisites third. 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?

For a no-parameter, no-output-schema read tool this is nearly sufficient, and auth/approval context is a genuine plus. However, 'recent' is never defined and the shape of the returned usage totals is left entirely unspecified, which matters since there is no output schema to fall back on.

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 nothing for the description to disambiguate and the baseline applies. The mention of 'recent' hints at an implicit time scope that is not parameterized, which is the only residual ambiguity.

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 and resource ('Read recent EXZA commander call counts') and immediately distinguishes itself from the sibling that returns per-call records. An agent can tell what it gets back 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 names exza_list_commander_call_history as the alternative and gives the discriminating condition: usage totals versus per-call records. It stops short of stating when counts are insufficient or any exclusion beyond that single sibling, so it is clear but not fully exhaustive.

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