List error signatures

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

Annotations already cover read-only, idempotent, non-destructive behavior. The description adds useful behavioral details beyond annotations: the 400 invalid_period refusal for periods exceeding plan retention, and the pagination behavior (page past end returns last page). This goes beyond the schema and helps the agent anticipate edge cases.

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 with no filler. The first sentence states the function and output, the second explains the purpose. Information is front-loaded and every word earns its place. Excellent structure.

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?

Given the tool has 4 parameters, full schema coverage, annotations covering safety, and an output schema, the description is complete enough. It explains the grouping concept, the period constraint, and the error behavior. The only minor gap is that it does not describe the return format, but the output schema covers that. A 4 reflects strong completeness without being perfect.

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 all parameters are already well-documented. The description does not add significant parameter-level meaning beyond what the schema provides; it mentions 'period' conceptually but does not elaborate on parameter syntax or constraints. Baseline 3 is appropriate.

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 states a specific verb ('list') and resource ('error signatures') and explains the grouping by fingerprint with frequency and recency. It also gives the core question it answers, which clearly distinguishes it from siblings like list-flaky-tests or get-run. No ambiguity about what this tool does.

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 description provides a clear context for when to use it: to determine if a failure is a recurring instance. It implies a use case but does not explicitly name alternatives or state when not to use it. Still, the guidance is concrete and not misleading, so it earns a 4.

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