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

With only readOnlyHint available, the description carries the burden well: it discloses the denominator semantics (reported 13F long-equity value, explicitly not AUM), the single-quarter no-fabricated-turnover rule, the refusal path (DATA_UNAVAILABLE on unreachable store), data provenance/licensing, and that caveats arrive in tool_notes. This is a genuine edge-case map.

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, then routing, then semantics, then caveats — good ordering and no filler sentences. It is dense with parenthetical asides and ALL-CAPS emphasis, which costs a little readability but every clause adds information.

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?

No output schema exists, and the description compensates by naming the return shape ({summary, fund, quarter, n_positions, reported_long_equity_value, analytics}) plus where caveats land. For a one-parameter analytics tool with only a readOnlyHint annotation, nothing an agent needs to call it correctly 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 100% and the single param is self-documenting, so the baseline is 3. The description adds real meaning beyond the schema: the CIK must be NUMERIC and a ticker 'will not resolve here', which the schema's 'e.g. 1067983' does not state.

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+resource: computes institutional-filer behavior analytics from 13F holdings, naming the exact metrics (concentration/top-N %, normalized HHI, turnover, persistence). It explicitly distinguishes itself from the two nearest siblings, get_13f_holdings (position lists) and ol_13f_filer_search (CIK resolution).

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?

Explicit routing: use ol_13f_filer_search when you only have a ticker, and use get_13f_holdings if you need a position list ('NO position list'). The 'when-not' cases are stated as clearly as the 'when'.

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