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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so safety behavior is fully covered elsewhere. The description's added value is telling the agent what the returned record contains (aim, idea, tip), which matters because no output schema exists. It says nothing about error behavior for an unknown id or about the lang parameter's effect.

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 short sentences, front-loaded with what the tool returns and followed by the prerequisite. No filler or repetition of the title.

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 two-parameter, read-only lookup with full schema coverage and complete annotations, the description supplies the one thing structured data lacks — the shape of the returned content. Only the failure mode for an invalid id is unaddressed.

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%: id's provenance and example (applied_safety_01) and lang's allowed values are already documented in the schema, and the description only echoes the id source. Baseline 3 applies since the schema does all parameter 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?

The description names the resource (a single BillyGo practice pattern) and enumerates its contents — goal, underlying idea, and coaching tip — which clearly separates it from billygo_list_patterns. It never uses an explicit retrieval verb, but the content inventory makes the operation unambiguous.

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?

"Get ids from billygo_list_patterns" gives an explicit prerequisite and points at the sibling that supplies the required id, effectively routing the agent. It does not state when-not-to-use (e.g. listing all patterns), but for a trivial by-id lookup that omission is minor.

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