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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the description adds real value on top: the admin-scope auth requirement, the 7-day observation window, the RED interpretation rule ('N failures, 0 lessons'), and an explicit data-boundary statement that output is counts only with no log text or repository. Missing only rate/volume or pagination behavior, which matters little for a fixed-window aggregate.

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 admin prerequisite is front-loaded and the body is dense with concrete facts rather than filler. Minor weakness: 'Also each pattern's count and register row, and the register' is awkward and partly redundant with the trailing 'Returns {health, patterns, register}'.

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 input parameters and no output schema, the description carries the whole burden and does so: it names the three return keys, defines the health signal's RED condition, and states what the counts exclude. An agent can decide to call it and interpret the result without further information.

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 of 4 applies. The description correctly does not invent parameter guidance, instead spending its words on semantics of the returned data.

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 subject: whether CI failures are being converted into lessons, enumerating the tracked signals (classified failures, lesson.pattern events, recurring candidates, >1h unresolved failures) over a 7-day window. It is clearly not a generic health check like merjax_ci_health or merjax_ci_queue_status, though it never explicitly names those siblings to draw the boundary.

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?

It gives a hard prerequisite ('Site admins only, needs an admin-scoped token') and implies the auditing use case via the 7-day window and RED threshold. However, it never says when to call this instead of merjax_ci_health, merjax_explain_failure, or merjax_list_flaky_tests, so alternative selection 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.