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

With no annotations, the description carries the full burden. It discloses the return values (WITHIN_MANDATE, EXCEEDS_MANDATE, EXPIRED) and the remaining budget, plus an important behavioral warning about not splitting spends. It also clarifies the mandate's scope and non-custodial nature, which is critical context beyond the basic function.

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 well-structured and front-loaded. The first sentence states the purpose, followed by return values, then a critical warning, and finally a scope note. Every sentence earns its place and the length is appropriate for the tool's complexity.

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 no output schema, the description fully covers what the tool does, how to interpret results, how to react to an exceedance, and the scope of the mandate. It equips an agent with all necessary context to select and invoke the tool correctly.

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?

The input schema already provides full 100% coverage for both parameters: amount is 'proposed spend in base units' and mandateId is 'the mandate digest'. The description adds no new parameter-level semantics beyond what the schema states, so the baseline of 3 is appropriate.

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 checks a proposed spend against a signed spending mandate before making it. It names the specific action (check), the resource (mandate), and the timing (before spending), distinguishing it from siblings like robyn_mandate_status that likely only query mandate status.

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 explicitly says to use it BEFORE making a spend, provides a clear directive for the EXCEEDS_MANDATE case (do not split, ask to raise budget), and notes the scope limitation (mandate covers only spending through Robyn). This gives strong when-to-use and when-not-to-use guidance, even without naming alternatives.

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