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

With no annotations provided, the description carries the full behavioral burden and does so excellently. It discloses the async turnaround time, that the API reply is only an acknowledgment, that polling is not needed, that the PDF is processed in memory and never stored, and that payment is via Bitcoin Lightning with no account or card.

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 compact and front-loaded with the primary purpose, then covers pricing, async behavior, privacy, and payment prerequisites in a logical order. Every sentence adds meaningful operational detail; there is no fluff or 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 paid, async, privacy-sensitive tool with no output schema, the description is remarkably complete. It covers what the tool does, the prerequisite payment step, expected delay, the acknowledgment-only reply, privacy handling, cost, and payment method. Nothing critical is missing for an agent to invoke it 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?

Schema coverage is 100%, so the baseline is 3. The description adds value beyond the schema by explaining the flat 1000 sats pricing, the requirement to first create a payment with toolName='e_signature', and the expectation that the signed copy is emailed to the customer. It doesn't deeply elaborate every parameter, but the schema already does that.

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 and resource: send a document out for legally binding e-signature, with the signed copy emailed back. It clearly differentiates from siblings like send_email or send_fax by focusing on the signature workflow and provider-based fulfillment.

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 on when to use the tool: for legally binding e-signatures with multiple signers and async delivery. It also names the necessary prerequisite create_payment with toolName='e_signature' and explicitly says there is nothing to poll. It does not name alternatives or when-not-to-use cases, but the use case is sufficiently distinct.

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