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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint false, which the description aligns with. The description adds meaningful behavioral context beyond the annotations by documenting the batch response shape `{ results, errors }` and the specific fields returned. It does not cover error details or rate limits, but given the strong annotation coverage, this is acceptable.

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 well-organized, front-loading the primary action and then enumerating return fields and usage notes. The long field list is arguably necessary given the tool's complex output and the absence of an output schema. It remains efficient by using compact notation like 'interestRates[] (taxType, ratePercentage, indexer)' rather than lengthy prose.

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?

For a read-only detail endpoint with no output schema, the description covers all essential context: the exact input format, batch limits, return payload structure (fields and nested objects), and placement in the workflow. The `{ results, errors }` shape and installments breakdown leave no major ambiguity about what the agent can expect.

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 provides only the parameter name `loan_ids` with no description (0% coverage). The description compensates by explaining to pass `loan_ids` as an array and noting the 1-50 limit. This adds practical semantics that the schema alone does not provide, though it could have explained the meaning of the IDs further.

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 clear verb+resource: 'Returns full loan contract detail by id'. It also names the exact endpoint and enumerates the returned fields, making the tool's purpose unmistakable. The phrase 'Use after openfinance_list_loans to deep-dive on a specific contract' explicitly distinguishes it from its list sibling.

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?

The description gives explicit usage guidance: 'Use after openfinance_list_loans to deep-dive on a specific contract.' It also specifies the batch size (1-50) and how to pass loan_ids as an array. This directly tells the agent when to use this tool relative to its sibling tools.

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