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

Beyond the readOnlyHint annotation, the description discloses that access is restricted to the caller's own signals and that unauthorized ids return not_found without revealing existence — a meaningful security behavior an agent must know. It also warns that text fields are untrusted alert data, mitigating prompt injection, though it says nothing about the returned record's shape.

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 carrying distinct information: scope, authorization/error behavior, and data-trust warning. It is telegraphic in places ('One signal by id') but front-loaded and free of filler.

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 output schema, the description should hint at what a signal record contains; instead it only mentions untyped 'text fields' from alerts. Access control and error semantics are well covered, but the return payload is left opaque for a tool whose whole job is returning a record.

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 schema has 0% description coverage, and the description only restates that lookup is 'by id' without explaining the integer's origin, format, or whether it comes from recent_signals. It adds marginal meaning over the schema's bare "id: integer".

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?

"One signal by id" states a specific resource and scope, making clear this is a single-record fetch rather than a listing. It implicitly contrasts with the listing sibling recent_signals, though it never names that sibling to make the distinction explicit.

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 single-record framing implies when to use this over a listing tool, and the ownership constraint ('only your own signals') is stated. However, no sibling is named and there is no explicit when-not-to-use guidance, so the routing 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.