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 mentions the return content ('complete budget details including spending limits, period configuration, and current status'), which adds some behavioral context. However, it lacks details on error handling, authentication needs, rate limits, or whether it's read-only (implied by 'Retrieve' but not explicit), leaving significant gaps for a tool with no annotation coverage.

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 two sentences that are front-loaded and efficient: the first states the purpose and key input, and the second specifies the return details. Every sentence adds essential information with zero waste, making it appropriately sized and well-structured.

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 (1 parameter, 100% schema coverage, no nested objects) but lack of annotations and output schema, the description is adequate but incomplete. It covers the purpose and return content but misses behavioral aspects like error cases or operational constraints, making it minimally viable but with clear gaps for an agent to rely on.

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%, with the single parameter 'budget_id' documented as 'Unique budget identifier'. The description adds no additional meaning beyond this, such as format examples or constraints, so it meets the baseline of 3 where the schema does the heavy lifting without extra value from the description.

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 budget'), and key identifier ('by its unique ID'), distinguishing it from sibling tools like 'get_budgets' (plural) which likely returns multiple budgets. It precisely defines the tool's function without being vague or tautological.

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 specifying 'by its unique ID', suggesting this tool is for fetching a specific budget when the ID is known. However, it does not explicitly state when to use this versus alternatives like 'get_budgets' or provide any exclusions or prerequisites, leaving some ambiguity in context.

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