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

With only readOnlyHint available, the description carries the burden and delivers: curated narrow universe (never live EDGAR full-text), prefix-match ranking, refusal semantics on unreachable store, and data provenance. This is substantial behavioral context beyond the annotation.

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 purpose and alternative routing, then return shape, then universe caveat. Dense but each clause carries signal; a few length/cap details repeat the schema and are slightly redundant.

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?

Despite no output schema, the description fully specifies the return object shape ({summary, query, filers:[{cik, name, last_filing, page_url}], count}) and the empty/error cases, so an agent has everything needed to call and interpret it.

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 100% so the 3-80 char and 10-cap constraints are already documented; the description largely restates them. It does add one semantic beyond the schema, the 'name-PREFIX matches rank first' ordering behavior, which lifts it above the baseline 3.

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 precise verb+resource ('Resolve a 13F FILER name to its CIK') and immediately distinguishes itself from siblings by naming get_13f_holdings, ol_13f_filer_analytics, and contrasting with search_company which 'resolves ISSUERS'. An agent can route without opening another 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 frames itself as 'the front door' to the holdings/analytics tools for when the manager is known but the CIK is not, and names search_company as the alternative for issuers. It also gives the when-empty vs when-unreachable distinction (filers=[] vs DATA_UNAVAILABLE).

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