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

Annotations already provide readOnlyHint=true, idempotentHint=true, destructiveHint=false. The description adds valuable behavioral context by listing the specific return fields and the batch result/errors structure. It does not mention side effects or permissions, but none are relevant for a read-only GET endpoint. The added detail goes beyond annotations without contradicting them.

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 front-loaded with the core action and endpoint, then lists specific return fields in a compact, well-structured format. Each sentence serves a purpose: what it does, what fields to expect, when to use it, and how to pass parameters. No wasted words.

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 no output schema, the description thoroughly enumerates the response fields (interestRates, contractedFinanceCharges, balloonPayments, etc.), covers the parameter constraint, and provides usage guidance. It also discloses the batch response shape. For a read-only detail endpoint, this is highly complete.

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 only defines loan_ids as an array of strings. The description adds essential meaning: 'Pass `loan_ids` as an array (1-50)' – specifying the array length constraint and invocation pattern. It also clarifies this is a batch operation. This directly compensates for the 0% schema description coverage.

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 opens with a specific verb and resource: 'Returns full loan contract detail by id (GET /loans/:loanId)'. It clearly distinguishes from siblings like openfinance_list_loans by positioning itself as a follow-up deep-dive tool. The scope and output are well-defined.

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 states when to use: 'Use after openfinance_list_loans to deep-dive on a specific contract.' This gives a clear sequential context and differentiates from the list tool. It also notes the batch shape (`{ results, errors }`), which is important for correct invocation.

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