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. It discloses key behavioral traits: pagination support, date filtering, merchant search, amount filters, and that it returns complete expense objects with money annotation and summaries. However, it doesn't mention authentication requirements, rate limits, error handling, or whether this is a read-only operation (though 'fetch' implies read). The description adds value but lacks comprehensive behavioral context.

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 appropriately sized at two sentences, front-loaded with the core purpose, and each sentence adds value: the first defines the tool and scope, the second lists features and return format. There's no redundant information, though it could be slightly more structured (e.g., bullet points for features).

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 complexity (11 parameters, no annotations, no output schema), the description is moderately complete. It covers the tool's purpose, key features, and return format, but lacks details on output structure (beyond 'complete expense objects'), error cases, or performance considerations. Without annotations or output schema, more behavioral context would be beneficial for a tool with many parameters.

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 the schema already documents all 11 parameters thoroughly with descriptions, constraints, and enums. The description adds marginal value by mentioning 'date filtering, merchant search, and amount filters' which aligns with parameters like start_date, end_date, merchant_name, min_amount, and max_amount, but doesn't provide additional syntax or usage details beyond what the schema specifies. Baseline 3 is appropriate when 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?

The description clearly states the tool fetches card expenses across multiple pages with pagination and filtering capabilities. It specifies 'card-specific endpoint' which distinguishes it from the sibling 'get_all_expenses', though it doesn't explicitly contrast with other card-related tools like 'get_card_expense' or 'get_card_transactions'. The verb 'fetch' and resource 'card expenses' are specific.

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 by mentioning it's 'similar to get_all_expenses but card-specific', which suggests when to use this over the general expense tool. However, it doesn't provide explicit guidance on when to use this versus other card-related tools like 'get_card_expense' (singular) or 'get_card_transactions', nor does it mention any prerequisites or exclusions for usage.

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