mercury_list_credit_transactions

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

Given no annotations, the description carries the full burden. It discloses that `pending` items are card authorisations that may still be reversed, and returns a specific structure snippet. It does not contradict any annotations (none provided). A minor gap is lack of mention of rate limits or idempotency, but for a read tool this is sufficient.

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?

Description is lean and well-structured with clear sections (USE WHEN, DO NOT USE, RETURNS). Every sentence serves a purpose, no filler. Front-loaded with core functionality.

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?

Schema covers all parameters, description adds use-case context and sibling differentiation. Returns format is given in snippet. Could mention pagination defaults (limit/offset), but schema already includes that. Overall complete for a list tool.

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 baseline is 3. The description adds value by stating `accountId` comes from `mercury_list_credit_accounts` and explaining `pending` status meaning. However, no further detail beyond schema is provided for other parameters.

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 clearly states the tool lists transactions on a Mercury IO Credit card account, including pending authorisations. It explicitly distinguishes from the sibling `mercury_list_transactions` by noting the credit vs deposit account difference and the shared API endpoint. This provides specific verb+resource scope with sibling differentiation.

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?

Explicit 'USE WHEN' and 'DO NOT USE' sections provide clear guidance: use for auditing credit card spend, reconciling, or building card-level view; do not use for deposit-account transactions (referencing `mercury_list_transactions`). It also advises filtering by `status: 'sent'` for posted transactions only.

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