lookup_code

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It does well by stating what the tool returns (code details, descriptions, RVU values, Medicare policies) and providing concrete examples. However, it doesn't mention important behavioral aspects like rate limits, authentication requirements, error handling, or whether this is a read-only operation (though implied by 'look up').

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 perfectly structured: a clear purpose statement, followed by what it returns, then usage guidance, and finally concrete examples. Every sentence adds value with zero waste. The examples are relevant and illustrative without being verbose.

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 tool with 5 parameters, 100% schema coverage, but no annotations or output schema, the description does quite well. It explains the tool's purpose, what it returns, and when to use it. The examples provide concrete usage patterns. The main gap is the lack of output format details (since no output schema exists), but the description compensates by listing the types of information returned.

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%, so the schema already fully documents all 5 parameters. The description adds minimal parameter semantics beyond the schema - it mentions the types of codes (CPT, HCPCS, ICD-10, NDC) which aligns with the code_system enum, and the examples show code formats. This meets the baseline of 3 when schema coverage is high.

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 clearly states the tool's purpose: 'Look up a medical code... and get coverage information.' It specifies the exact action (look up), resource (medical codes), and output (coverage info, code details, descriptions, RVU values, Medicare policies). The examples reinforce this by showing specific code lookups, distinguishing it from sibling tools like check_prior_auth or search_policies.

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 provides clear context for when to use this tool: 'Use this to understand what a code means and whether it's covered.' This gives practical guidance on its primary use case. However, it doesn't explicitly mention when NOT to use it or name specific alternatives among the sibling tools, which prevents a perfect score.

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