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

Annotations already cover readOnly/idempotent/non-destructive, so the bar is lower, and the description still adds real behavioral context: adaptive runs are excluded, moves are only reported where two intervals separate, method-version changes are flagged as a method break, and the default scope is account-only. These are substantive methodology disclosures not derivable from structured fields.

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?

Four sentences, front-loaded with the purpose before the methodological caveats. Every sentence carries content, though the interval/method-break detail is dense for a single block of text.

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?

An output schema exists, so return values need no explanation, and the description still sketches them. Combined with the exclusion and method-break rules, an agent has enough to call it correctly; only the sibling-routing information is missing.

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%, with 'key' and 'scope' both documented including enum values, so the baseline is 3. 'Default returns the account scope only' restates the schema's declared default and adds no syntax or format detail beyond it.

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 ('see how often the client was named on each scheduled run over time') and names the unit of return (count, base, 95% interval). It is clearly distinct from compare_runs semantically, but does not explicitly name siblings or contrast itself with 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?

'Use this to see how often...over time' gives valid context for when the tool applies, and 'Adaptive runs are excluded' scopes the data. However, there is no guidance on when to prefer this over compare_runs, get_results, or list_runs, so the alternative-selection burden is left to inference.

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