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

The readOnlyHint=true annotation already establishes this is a safe read operation, so the description only needs to add context. It contributes the underlying REST endpoint (GET /external_accounts) and the status.in query encoding, which are useful, but says nothing about pagination limits, result ordering, or empty results.

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?

Three short sentences, each earning its place: what it lists, the backing endpoint, and how filtering works. The core scope is front-loaded with zero filler.

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 low-complexity read-only list tool with full schema coverage and a covering readOnlyHint annotation, the definition is nearly sufficient. A brief note on return shape or default pagination behavior would fully close the gap, but nothing critical is missing.

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 description coverage is 100%, so all three parameters (limit, cursor, status) are already documented in the schema. The description's note about status being sent as status.in duplicates the schema text rather than adding new meaning. Baseline 3 applies when the schema does the heavy lifting.

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?

States a specific verb (List) and resource (external/counterparty bank accounts), and the parenthetical '(counterparty)' explicitly distinguishes it from the sibling increase_list_accounts, which lists internal accounts. An agent can pick the right tool without opening either schema.

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?

It hints at usage by noting the status filter and its wire format, but gives no explicit when-to-use guidance, prerequisites, or exclusions relative to siblings like increase_get_account or increase_list_accounts. Usage is implied rather than stated.

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