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

Annotations already mark readOnlyHint=true and destructiveHint=false, but the description adds valuable behavioral context: the authentication requirement ('Public reports need no key; a caller's own reports need theirs') and the specific output payload. This goes beyond what the annotations alone provide, justifying a 4.

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 sentences with zero redundancy. The primary action and scope are front-loaded, and the auth note is placed at the end. Every word contributes to the agent's understanding.

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?

The tool has an output schema, so return format is covered elsewhere. The description covers the purpose, the input origin, the returned content, and auth requirements. Minor omissions like error handling are acceptable given the simplicity and the presence of structured schema.

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 input schema already describes the single parameter 'id' as 'A result id from search (a run id)' with 100% coverage. The description repeats the source of the id ('the id search returned') without adding new syntax or format details. Baseline 3 is appropriate since the schema does the heavy lifting.

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 ('Read') and a clear resource ('one report by the id search returned') and enumerates the exact contents returned (full markdown text, citations, evidence header, title, url, metadata). This clearly distinguishes it from sibling tools like runs.get (likely for raw runs) and search (for finding ids), so an agent can immediately understand its role.

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 'by the id search returned' establishes the intended workflow (use after search) but does not explicitly name alternatives or state when not to use it. There is clear contextual guidance without exclusions, which matches a 4.

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