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

Annotations (readOnlyHint, idempotentHint, destructiveHint) already indicate safe read operation. Description adds behavioral context by noting batch response shape '{ results, errors }' and enumerating returned fields (interestRates, installments, etc.), which goes beyond what annotations provide.

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?

Single sentence packs many field names and guidance, but remains readable. Could benefit from bullet points for the field list, but it is concise with 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?

With no output schema, description enumerates key returned fields (interestRates, charges, installments, dates) and input constraints (array size). Also mentions batch shape. Missing details on pagination or potential errors, but adequate for the tool's simplicity.

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 0%, so description must compensate. It adds meaning by noting array size limit (1-50) and batch response shape. Though schema lists one parameter, description provides actionable constraints and error handling pattern, adding value beyond the raw schema.

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?

Description starts with 'Returns full loan contract detail by id' and lists specific fields, clearly indicating the tool retrieves detailed loan data. It explicitly distinguishes from sibling tool openfinance_list_loans by advising to 'use after' it for deep-diving on a specific contract.

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?

Provides explicit guidance: 'Use after openfinance_list_loans to deep-dive on a specific contract.' Also specifies input constraints ('Pass loan_ids as an array (1-50)'). Missing explicit when-not-to-use instructions, but context is clear.

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