filings_filing

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

Annotations already declare read-only, idempotent and non-destructive, but the description adds material context they don't cover: x402 pricing in USDC on Base, free with an API key, and that an unauthenticated call returns HTTP 402 with a decoded price in payment_required rather than being a hard failure. That paywall/error semantics is exactly the kind of behavior an agent cannot infer from structured fields.

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 definition, then a concrete example, then the routing rule, then the payment/behavior note. Every block is short and purposeful, with no filler or repetition.

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 single-parameter, no-output-schema read tool, the description covers what is returned, how to identify the resource, when to prefer a sibling, and the notable 402 payment path. Nothing an agent needs to invoke it successfully 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% and the single parameter is already documented with an example in the schema. The description's inline example accession and curl-style path only restate that example, adding no new semantics such as format validation or normalization rules. Baseline 3 is appropriate when the schema carries the meaning.

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 resource (one filing) keyed by accession number, plus what comes back (parsed items or insider transactions and the SEC document link). It explicitly distinguishes itself from filings_search, so an agent can route correctly without opening either 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?

Names the precondition ('when you have an accession number') and the exclusion ('Not for searching (use filings_search)'), pointing at the exact sibling to use instead. This is explicit when/when-not/alternative guidance.

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