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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), but the description adds real context: results are token-scoped to the calling agent, the tool is free, and the return payload format is illustrated. These are not derivable from the annotations or schema.

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?

The core payload (what it returns and when to call it) is front-loaded and every sentence is informative. Slight slack from the capitalized emphasis, the inline example, and the trailing 'Free.', but nothing is genuinely wasted.

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 zero-required-parameter read tool with an output schema, the definition covers scoping, timing, cost, and result shape adequately. The only gap is that it duplicates return-value detail the output schema already carries rather than adding more.

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 single optional 'limit' parameter has 100% schema description coverage including its default of 5, so the schema fully documents it. The description adds no syntax or format guidance for limit, which is the expected baseline when the schema does all the work.

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: returns this agent's recurring failure patterns from past diagnoses, with the exact shape of the result (failure classes, counts, percentage shares) and a concrete example. It is clearly distinguishable from siblings like my_impact and my_usage.

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 says 'Call it before a run to know what to guard against,' giving a concrete usage moment. It does not name a competing sibling or state when NOT to use it, so it falls short of the 5 tier.

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