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

Annotations already indicate readOnlyHint=true and openWorldHint=true, so the description does not need to restate those. It adds substantial behavioral detail beyond annotations: failure behavior when the item heading is hidden, response fields (accessionNumber, filingDate, source URL, parserVersion), latency for large filings, cost per call, payment method, and a reference to a public accuracy evaluation. This is rich and directly helps the agent anticipate outcomes.

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 a single paragraph but slightly long. However, every sentence earns its place: purpose is front-loaded, followed by the value proposition, accession behavior, failure mode, response contents, accuracy, latency, cost, and payment. It is efficient given the amount of critical operational information, though it could be tightened by grouping related points.

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 no output schema and five parameters, the description covers all necessary information: input semantics (via parameter details), output structure (response fields), failure modes, operational characteristics (latency and cost), and authentication requirements (credit key or machine payment). Nothing an agent needs to call it correctly or interpret 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 description coverage is 100%, so baseline is 3. The description adds extra meaning for 'accession' by explaining the default behavior when omitted, and for 'item' by noting that omitting it lists available items. It also clarifies the function of 'max_chars' implicitly through the truncation context. These additions go beyond the schema descriptions without repeating them, adding agent-relevant nuance.

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 ('pull') and resource ('single numbered item out of a 10-K or 10-Q'), and names common items like 1A, 7, and 1. It clearly distinguishes from sibling tools like compare_filings or edgar_search by focusing on extraction of one section as clean text, with no ambiguity about scope.

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?

Provides explicit usage context: explains why to use it ('saves you fetching a multi-megabyte HTML document'), and describes the difference between providing an accession number (pins exact filing) versus omitting it (gets most recent filing) with a warning about amendments. It also notes that omitting 'item' lists available items. However, it does not explicitly name sibling alternatives or state when not to use it, leaving some inference to the agent.

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