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

Annotations only declare readOnlyHint, so the description carries the burden and delivers: it warns that each BDC is read at its most recent filing so rows MIX dates and as_of_range must be read before treating marks as contemporaneous, notes debt positions only, names the source (SEC EDGAR schedules of investments, ol-derived), flags FREE, and states caveats ride in tool_notes.

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?

Dense but front-loaded: the core question comes first, then return fields, then the critical as_of caveat, then caps, cross-tool pointer, source and provenance. Every clause carries operational 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?

With no output schema, the description enumerates the returned fields (borrower, borrower_norm, holder_count, holder_tickers, holders, total_fair_value, total_par_amount, as_of_oldest/as_of_newest), discloses caps and data-source caveats — everything an agent needs to call and interpret it correctly.

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 baseline is 3; the description adds behavioral meaning by stating the caps as truncation rules (bdc_tickers truncated at 25, limit 50/200, min_holders max 50) and by explaining what min_holders semantically answers ('what is SHARED').

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 with scope: the cross-portfolio borrower intersection across a given set of BDCs, illustrated with a concrete question. It implicitly distinguishes itself from ol_bdc_top_borrowers (single BDC's book) and points to ol_bdc_borrower_dispersion as the follow-on.

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?

Clear when-to-use framing ('common to a GIVEN SET of BDCs') and the schema's min_holders text routes single-BDC lookups to ol_bdc_top_borrowers, with a pointer to ol_bdc_borrower_dispersion for pricing. No explicit when-not-to-use statement beyond that, so not a full 5.

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