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

Annotations already declare readOnly, idempotent, non-destructive and open-world, so the safety profile is covered by structured data. The description adds genuine behavioral context beyond that: it clarifies that an originator filter is a trust-level sponsor filter (most trusts are single-originator) rather than a per-loan lender lookup, and notes a query type the pack deliberately omits.

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-loads what the tool returns (one row per month, balance/loan count, bucket breakdown, weighted-average APR/FICO, 60+ DPD rate) before the filtering caveats, and every clause carries information. It is dense and runs long in a single block, which slightly hurts scannability.

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 fully specifies the return shape — one row per reporting month plus the full delinquency-bucket breakdown and derived DPD rate — and flags the deliberate data limitation. An agent has everything needed to call it and interpret results.

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 goes beyond the schema by disambiguating originator — it is a case-insensitive substring match on the trust's sponsor/depositor and semantically a trust-level filter, not a lender lookup — which is the field an agent is most likely to misuse.

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: sector-wide auto ABS delinquency aggregated by month across every tracked trust in one asset class. The phrase 'aggregated across every tracked trust' combined with 'sector-wide' distinguishes it from the trust-level siblings abs_trust_performance and abs_trusts, and an example query is given to disambiguate intent.

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 context for use (sector-wide view, optional narrowing to one sponsor/originator) and it explicitly rules out a related need: there is no loan-level 'which trusts hold loans from lender X' query. It stops short of naming the sibling tools to route to for per-trust detail, which is the only gap.

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