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

Annotations already declare readOnlyHint=true and destructiveHint=false, covering the safety profile. The description adds valuable behavioral detail by stating that 'Unknown ids return found:false,' which is not available from annotations alone. This is a meaningful addition for an agent handling missing results.

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 description is two short sentences with no filler. The primary action is front-loaded, and the additional not-found behavior is stated in a concise, direct second sentence. Every word earns its place.

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 simple one-parameter lookup with a readOnly annotation and an output schema present, the description is complete. It covers the core operation, the parameter's meaning, and the edge case of unknown IDs. Nothing critical is missing for an agent to invoke this correctly.

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 coverage is 0%, so the description carries the burden of explaining the parameter. It clarifies that 'id' refers to a measure_id, giving semantic meaning beyond the raw schema field. For a single simple string parameter, this is adequate compensation.

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 and resource: 'Lookup one Measure by measure_id.' It clearly distinguishes this from list/search siblings by emphasizing a single ID-based lookup. The behavior for unknown IDs is also specified, making the tool's purpose 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?

The phrase 'Lookup one Measure by measure_id' clearly implies this is the tool to use when you have a single known measure ID, as opposed to list or search tools. It does not explicitly name alternatives or exclusions, but the context from sibling names makes the usage clear enough.

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