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

Annotations already declare readOnly, idempotent, non-destructive and open-world, so safety is covered. The description adds real behavioral context (digit-only comparison, magnitude-blind matching, ranking by exactness and label overlap, 10-match cap, search scope controlled by filename), but a 3 is appropriate because much of the text also repeats what the schema and return contract already convey.

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?

Front-loaded with the core assertion and highly dense, but the matching-rule paragraph is long and repeats the magnitude caveat twice (once in the rules, once in the return section). Slightly verbose for the payload it delivers.

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?

An output schema exists, yet the description still names the return fields and explains how to use highlight_url and interpret found=false, which is exactly the operational guidance needed. Nothing required to invoke or act on results is missing.

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 coverage is 0%, so the description carries the full burden and largely does: cik gets a format example, value gets detailed normalization rules and a one-significant-digit caveat, label is explained as a ranking signal, and filename explains its scoping effect. Only accession_number lacks a format example, a minor gap.

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?

States a specific verb and resource ("check that a number ... appears in a filing") plus the exact matching semantics. It is clearly distinguishable from siblings like check_citations (citations) and verify_quote (quotes) without opening a schema.

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?

Explicitly states when to use it (before attributing a figure to a filing), what found=false means and how to react (do not attribute; say it was calculated and cite inputs), and how to handle derived numbers. Covers both the positive and negative cases.

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