far_clause_lookup

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

Discloses farOverhaulRisk caveat about codified FAR supersession, describes return fields (heading, revision date, kind, regulation, full text, prescribing section, ecfrUrl), and states that absent clauses return a not_found error. This goes well beyond the readOnlyHint and openWorldHint annotations.

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 dense and informative, front-loading the core purpose and key differentiator. It contains a useful caveat about farOverhaulRisk and error handling. While slightly long, every sentence adds value, so it earns a 4.

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?

With no output schema, the description fully enumerates return fields (heading, revision date, etc.) and error semantics. Given the tool's regulatory complexity, the description is complete and leaves no ambiguity about what the agent can expect.

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 has 100% coverage with descriptions for all three parameters (clauseNumber, asOfDate, includePrescription). The description adds value by explaining the default behavior of includePrescription (true) and giving examples of clause formats. However, since schema already describes parameters, the description's incremental contribution is moderate.

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 it provides authoritative FAR/DFARS clause text and its prescription (use condition). It explicitly distinguishes from the sibling ecfr_search by warning that ecfr_search mis-ranks exact clause numbers, so this tool is the correct one for exact lookup.

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?

Explicit guidance to use this tool instead of ecfr_search for exact clause numbers, with a concrete example of why (mis-ranking 52.212-4). Also notes keyless access and error behavior for absent clauses, providing clear usage context.

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