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

Beyond the readOnly and idempotent hints, the description discloses important behavioral details: the {results, errors} batch shape, the possible provider_incident block with unreliable data, and guidance not to present those values as real. This adds significant context about data quality and failure modes.

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 three sentences with high information density. The first sentence states the purpose, the second gives parameter guidance, and the third warns about provider incidents. No wasted words, and the most important info is front-loaded.

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 simple read-only tool with one parameter and no output schema, the description covers the return shape, potential anomaly, and parameter constraints. It is complete enough for an agent to correctly invoke the tool and interpret results, even without an output schema.

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 no description for the parameter, so the description fully compensates by explaining the array format and the 1–50 item constraint. It also clarifies that each ID refers to an account, making the parameter's purpose unambiguous.

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 clearly states the tool returns full account objects with extended creditData per ID, using the verb 'Returns' and specifying the resource. It distinguishes itself from siblings like openfinance_get_account_balance and openfinance_list_accounts by focusing on detailed account objects.

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 provides clear context for usage: it specifies to pass account_ids as an array (1–50) and describes the batch response shape. However, it does not explicitly mention when to prefer this over alternatives like openfinance_list_accounts, leaving the differentiation to the purpose statement.

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