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

Annotations already declare readOnlyHint=true and destructiveHint=false, but the description adds value beyond that: it discloses that the tool returns a canonical Mandate with body JSON and JCS hash, produces a summary, and has zero money movement or pipeline execution. This gives the agent concrete behavioral expectations without contradicting the annotations.

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 tight sentences with no filler. The core purpose and key boundary ('does NOT move money') are front-loaded, and the additional return artifacts are described efficiently. Every clause 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?

For high-level tool selection, the description is complete: it explains what the tool is for, what it returns, and what it deliberately does not do. The existence of an output schema covers return details, and annotations cover safety. The only real gap is that the 10 parameters, especially their interdependencies and which combinations are meaningful, are left entirely to the schema names.

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 10 parameters and 0% schema description coverage, the description carries the full burden for parameter meaning. It adds none at all — no mention of amountCents, rail, signerId, accountNumberId, expiration, or any other field. The agent must infer meaning solely from parameter names, patterns, and enums.

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 ('Draft') and resource ('a payment'), then clearly describes the output ('ready-to-sign Mandate', 'body JSON + JCS hash', 'plain-language summary'). The explicit negative statement 'Does NOT move money or run the pipeline' sharply differentiates it from money-moving siblings like autonomous_pay or commit_transfer.

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 gives clear context for when to use this tool: when a payment needs human review before commitment. The boundary 'Does NOT move money or run the pipeline' and 'a human commits it by signing and submitting' function as usage guidance. However, it does not explicitly name alternatives or say 'use X instead when Y'.

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