Brex MCP Server

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

No annotations are provided, so the description carries the full burden. It discloses that the tool returns 'complete spend limit configuration' with details like authorization settings and current balance, which adds useful behavioral context beyond basic retrieval. However, it lacks information on error handling, permissions, or rate limits, which are important for a read operation.

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 and efficiently details the return content in the second. Every sentence adds value without redundancy, making it appropriately sized and well-structured for quick understanding.

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 low complexity (one parameter, no output schema, no annotations), the description is mostly complete. It clearly explains what the tool does and what it returns. However, without annotations or an output schema, it could benefit from more details on error cases or response structure, but it adequately covers the essentials for a simple retrieval 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?

With 100% schema description coverage for the single parameter 'id', the schema already documents it as a 'Unique spend limit identifier'. The description adds value by emphasizing that it retrieves 'by its unique ID', reinforcing the parameter's purpose, but does not provide additional syntax or format details. Since there is only one parameter, the baseline is high, and the description adequately complements the schema.

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 specific action ('Retrieve'), resource ('a single spend limit'), and key identifier ('by its unique ID'), distinguishing it from sibling tools like 'get_spend_limits' (plural) which likely returns multiple items. It explicitly defines the scope as a single entity retrieval operation.

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 when you need to fetch a specific spend limit by ID, but it does not explicitly state when to use this tool versus alternatives like 'get_spend_limits' (for multiple limits) or other sibling tools. No exclusions or prerequisites are mentioned, leaving usage context somewhat inferred rather than clearly defined.

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