Pick the best LLM

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds behavioral value by disclosing the output format ('Concise output, no list') and the single-answer nature, which is not captured in the annotations. No contradictions found.

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 sentences long, front-loaded with the core function then usage guidance. Every word earns its place, with no redundant filler or repetition of schema/annotation details.

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 single-parameter tool with rich annotations and an output schema, the description fully covers what the tool does and when to use it. The complexity is low, and the description is sufficient to guide correct invocation without requiring additional explanation of return values (handled by the output 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 schema description coverage is 100% and the 'purpose' parameter is thoroughly described with concrete examples ('summarizing 50-page commercial leases' vs 'summarization'). The tool description adds no additional parameter-level detail, so it appropriately relies on the schema. This meets the baseline of 3.

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 uses a specific verb ('Return') and resource ('the single best LLM for a stated purpose'), clearly distinguishing it from siblings like 'rank' by explicitly stating 'no list'. It is concise and unambiguous about what the tool does.

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 description states when to use the tool: 'Use when the user has settled on the criteria and just wants one answer.' This provides a clear context, but it does not explicitly name alternative tools (e.g., 'rank' for lists) or give when-not-to-use guidance, so it stops short of the highest bar.

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