budget

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

Outstanding given no annotations. Discloses enforcement timing ('pre-execution'), specific error code ('402'), and user safety guarantee ('not a surprise bill'). Explains default read behavior when action omitted, critical for a tool with zero required parameters.

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?

Four sentences, zero waste. Front-loaded with purpose, progresses through default behavior, mutation syntax, and enforcement guarantees. No repetition of schema details except where necessary for flow.

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 no annotations and 100% schema coverage, description adequately compensates by explaining return behavior (current status) and error conditions (402). Absence of output schema is mitigated by explicit behavioral descriptions, though explicit return value structure for 'set' operation is implied rather than stated.

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 coverage, baseline is 3. Description adds value by explaining default behavior when action is omitted, and clarifying that 'set' action performs 'create/update' operations. Effectively links action and budget_usd parameters conceptually.

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?

Clear verb+resource ('Check or set your execution budget') but 'execution budget' terminology implicitly distinguishes from sibling 'check_balance' (likely account funds) without explicit comparison. Dual-mode nature (get/set) is immediately apparent.

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?

Excellent guidance on defaults ('Without action param, returns current status') and required parameter combinations ('Use action='set' with budget_usd'). Missing explicit distinction from 'check_balance' or when to prefer 'get_ledger', but covers the two primary usage patterns clearly.

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