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

Beyond the annotations, the description discloses non-obvious behavior: it runs a 'four-check pipeline' and a 'per-agent autonomy fence,' and redirects out-of-envelope payments to human approval. This gives an agent useful insight into side effects and gating, though the pipeline steps and envelope criteria remain vague.

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 tightly-written sentences with no filler. The primary action is front-loaded, and the second sentence adds meaningful behavioral context without repetition.

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 a 4-parameter tool with no schema descriptions and substantial behavioral implications, the description is too thin. It omits parameter semantics, pipeline details, envelope determination, and what happens after human approval, leaving an agent to guess at critical invocation details.

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 0%, so the description must compensate, but it only mentions a 'signed payment mandate' at a high level. It does not explain the role of jcsHash, how serviceLevel affects execution, what format mandateBodyJson should take, or what signatureB64url signs.

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 states a specific verb ('Submit'), a specific resource ('a signed payment mandate'), and a clear purpose ('autonomous execution'). This distinguishes it from drafting/confirming payment tools, though it does not explicitly name sibling 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?

The phrase 'for autonomous execution' implies the intended use case, and the autonomy fence comment clarifies when human approval is triggered. However, it does not explicitly state when to use this tool versus draft_payment, confirm_payment, or other payment-related alternatives, leaving the routing partially to inference.

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