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

Annotations only signal non-read, non-idempotent, open-world behavior. The description adds critical behavioral context: these actions 'send invitations and can consume credits', 'wait for processing and creates or reuses email signers', and warns against duplicate assignments. It clearly discloses side effects and post-failure behavior beyond what annotations convey.

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 dense but well-organized: it front-loads the core purpose, then walks through each mode in a consistent pattern, and ends with a high-value failure-recovery warning. Every sentence adds non-redundant information and 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 description covers the three modes, preconditions, credit consumption, and failure recovery, which is substantial for a complex tool with no output schema. The only gap is that it does not explicitly describe the full return payload, though it hints at the retained document ID. Overall, it is nearly complete for safe and effective invocation.

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 goes beyond the schema by explaining the strategic meaning of the action discriminator (exactly one source) and the precondition for from_document and from_template parameters. It does not repeat field-level details but adds operational guidance that helps the agent choose and populate parameters correctly.

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 for signature') and immediately distinguishes the three execution modes: from_pdf, from_document, and from_template. Each mode has a distinct input source and outcome, and the high-level wording differentiates this tool from siblings like find_documents or save_signer.

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 explicit when-to-use guidance: 'using exactly one source', 'inspect the document first and do not repeat an existing assignment', and 'discover roles and field IDs first'. It also provides recovery guidance after partial failure: 'continue from_document instead of uploading again', which names the alternative action and the condition selecting it.

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