Look up one citation in the register

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

The description adds extensive behavioral context beyond annotations: it enumerates all possible statuses, explains that 'not in the register' is never proof of nonexistence, clarifies the meaning of red and orange rows, and discloses quota impact. This is consistent with the openWorldHint and readOnlyHint 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?

Although long, every sentence carries essential operational information: purpose, scope, statuses, exclusions, interpretive warnings, and quota behavior. The opening sentence front-loads the core function, and the rest is a compact structured list of caveats.

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 compensates fully by explaining what the tool answers, the statuses an agent may encounter, and how to interpret ambiguous or negative results. Nothing critical is missing for an agent deciding whether and how to invoke the tool.

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 single parameter is fully documented in the schema, which already explains that 'only the reporter citation is resolved.' The description adds concrete examples ('590 U.S. 644', 'Bostock v. Clayton County, 590 U.S. 644 (2020)') and clarifies that surrounding case name and year are acceptable, slightly enriching what the schema provides.

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 action ('look up a single case citation ... in proofread.law's register') and the exact question it answers, including the fields returned. It explicitly distinguishes itself from sibling tools by noting this is a register lookup and that a mismatch means 'the citation points elsewhere.'

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?

It gives explicit when-to-use guidance: 'Use it when one citation is in doubt; use check_citations for prose, and resolve_citations for a list.' It also lists clear exclusions ('Cannot: resolve Westlaw (WL) or Lexis identifiers, check statutes, regulations or secondary sources, or say whether a case is still good law').

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