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

With annotations already declaring readOnlyHint, openWorldHint, and idempotentHint, the description adds valuable behavioral context beyond them: it reveals possible statuses (ACTIVE, SUPERSEDED, REVOKED), the exact return envelope fields, and a 'graceful clean-slate envelope on missing / backend error.' This gives the agent insight into edge-case behavior that annotations do not cover, and it contradicts nothing.

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?

The description is dense but tightly organized: purpose → conditional behavior → return fields → workflow → complementary tools → error handling. Every sentence earns its place; there is no fluff or repetition of schema details. The structure front-loads the primary purpose and then logically builds to advanced usage.

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?

Given there is no output schema, the description compensates by enumerating the return fields and statuses. It also covers both invocation patterns, the error envelope, and references the on-chain Schema B payload, which is essential context for a forensic workflow. This is a complete description for a tool with moderate complexity.

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?

The schema has 0% description coverage, so the description must carry the full burden. It does so by explaining that lenderId identifies the lender and that methodologyHash, when provided, selects a specific version; when omitted, the active version is returned. This adds significant semantic meaning beyond the raw schema properties.

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?

The description starts with a specific verb and resource: 'Look up a lender's underwriting methodology by lenderId.' It clearly distinguishes two modes (with and without methodologyHash) and lists the return fields, making the tool's function unmistakable. Unlike sibling tools like get_methodology_versions or verify_lender, this focuses on a single methodology lookup, which is explicitly differentiated.

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?

Usage guidance is explicit: it explains when to omit methodologyHash (to get the current active methodology) and when to include it (to retrieve a specific version cited on an attestation). It also provides a forensic workflow with concrete steps, and names complementary tools (verify_lender, verify_credit_risk) for the full chain, giving clear context for when this tool is appropriate.

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