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

With no annotations, the description carries the full behavioral burden. 'Check' suggests a non-mutating validation, but it does not explicitly state read-only behavior, whether funds are reserved, side effects, or failure behavior.

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?

Two short sentences with no filler: the purpose is front-loaded, followed by a clear ordering instruction. Every sentence earns its place.

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?

The required parameters and pre-payment timing are clear enough to invoke the tool. However, with no annotations and no output schema, the return semantics and side-effect profile remain unstated, which leaves a meaningful gap for a budget check.

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%, and all three required parameters are documented in the schema. The description adds no parameter-level meaning beyond the schema's budget, amount, and vendor fields.

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?

States a specific verb and resource: 'Check' a 'purchase' against a 'budget.' This clearly distinguishes validation from sibling actions like create_budget or get_budget, though it does not explicitly name alternatives.

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?

Gives explicit timing guidance: 'Call BEFORE making a payment.' It does not explain when not to use it or compare it with alternatives such as get_budget or query_reservation.

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