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

With only readOnlyHint available, the description carries substantial extra behavioral burden: the units trap (raw `spread` mixes percent and bps; use `spread_bps`), stale-position exclusion by default, the 25 default / 100 hard cap, the source (SEC EDGAR schedules of investments), and that caveats ride the response's tool_notes. That is rich disclosure 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, then inputs, then return shape, then the units trap, then defaults and provenance. The parenthetical example and the dense field list all earn their place; no filler sentences.

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, yet the description enumerates the return keys ({summary, borrower_norm, count, lender_count, tranche_count, lenders, ...}), the row granularity per BDC lender, the sort order, and where caveats live. Combined with defaults, caps, and the unit warning, 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 already 100%, so baseline is 3, but the description adds real meaning: `limit` counts LENDERS not rows (with tranches nested), `include_stale` is tied to whether a lender's newest filing still names the borrower, and the spread/spread_bps distinction warns against using the raw field.

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 and resource — cross-lender loan-pricing dispersion for one private-credit borrower — and concretizes it with an example (one BDC marks S+550 @ 98, another S+575 @ 99). It is clearly distinguishable from siblings like ol_bdc_top_borrowers (which supplies the borrower_norm input) and ol_bdc_loan_pricing_trend.

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 tells the agent where to get the required borrower_norm (ol_bdc_top_borrowers or search_bdc_borrower) and describes the default vs. include_stale behaviour. It stops short of stating when NOT to use it versus closely related siblings such as ol_bdc_common_borrowers or ol_bdc_credit_quality.

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