Brex MCP Server

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It effectively describes key traits: automatic pagination (handling pagination automatically), status filtering capability, and the inclusion of money annotations on balance fields. However, it does not mention rate limits, authentication requirements, or error handling, leaving some behavioral aspects uncovered.

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 front-loaded with the core purpose in the first sentence, followed by supporting details in a logical flow. Each sentence adds value: fetching accounts, pagination, filtering, return details, and annotations. There is no redundant or wasted text, making it efficiently structured and concise.

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?

Given the tool's complexity (3 parameters, no output schema, no annotations), the description is fairly complete. It covers the purpose, behavior (pagination, filtering), and return details. However, without an output schema, it could benefit from more specifics on the return structure (e.g., format of account details), and it lacks information on error cases or prerequisites, leaving minor gaps in context.

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 input schema has 100% description coverage, providing clear details for all parameters (page_size, max_items, status). The description adds minimal value beyond the schema by mentioning 'Supports status filtering', which aligns with the schema's status parameter. Since schema coverage is high, the baseline score of 3 is appropriate, as the description does not significantly enhance parameter understanding.

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 verb ('Fetch') and resource ('all Brex accounts (card and cash)'), specifying the scope as all accounts with both card and cash types. It distinguishes from siblings like 'get_account_details' (single account) and 'get_all_card_expenses' (expenses only), making the purpose specific and differentiated.

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 implies usage for retrieving all accounts with filtering, but does not explicitly state when to use this tool versus alternatives like 'get_account_details' for a single account or 'get_budgets' for budget-related data. It mentions automatic pagination and status filtering, providing some context, but lacks clear exclusions or direct sibling comparisons.

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