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

Annotations already cover read-only and open-world access. The description adds meaningful behavioral context beyond them: that issuer_name resolution is best-effort and never a guaranteed join, whereas manager_cik is exact. It does not discuss pagination limits, but the schema carries those.

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?

A single sentence with the resource stated first and the two filtering modes clearly delineated by an em-dash. No filler; every clause carries meaning.

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?

With an output schema present, return values needn't be described, and all six parameters are fully documented in the schema with description semantics reinforced. The definition is complete for invocation; only cross-sibling routing is absent.

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 baseline is 3; the description adds the exact-vs-best-effort framing for manager_cik vs issuer_name/cusip that explains the reliability difference between the parameters, which is genuine semantic value.

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 (Search) and resource (institutional investment managers' quarterly 13F portfolio holdings), and distinguishes itself from the sibling facets tool by being the queryable search endpoint. An agent can identify the domain (SEC 13F) immediately.

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 splits usage into two modes — manager_cik for a manager's full portfolio vs issuer_name/cusip for who-holds-an-issuer — and flags the latter as best-effort. No when-not-to-use or sibling-routing guidance (e.g., vs datasets_sec_institutional_positions_facets or sec_institutional_holdings), so it stops short of a 5.

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