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

Annotations only flag destructiveHint=true; the description supplies the crucial detail behind that flag — isDraft defaults to true and sends nothing, while isDraft=false with real signers SENDS signature-request emails. That is exactly the side-effect disclosure an agent needs before invoking a destructive tool, plus a test-mode escape hatch.

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?

Four short sentences, front-loaded with the purpose and then escalating to the two behavioral warnings. Nothing is padding — the mutation name, draft default, and test-mode tip all earn their 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 an 8-parameter create tool with nested signer/file objects and no output schema, the description covers purpose, the main behavioral trap, and a dev-mode path. It omits what the call returns (e.g., a packet id/eid that would be needed to chain into anvil_generate_etch_sign_url or anvil_get_etch_packet), which is the one notable gap.

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 100%, so the schema already documents all eight parameters, including isDraft's default and email behavior. The description reinforces the risky defaults with emphasis but adds little semantic detail beyond what the schema states, which is the expected baseline when the schema does the heavy lifting.

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 — 'Create an Etch e-signature packet (documents + signers)' — and even names the underlying GraphQL mutation, so there is no ambiguity about what is created. It does not, however, explicitly differentiate itself from adjacent siblings such as anvil_get_etch_packet or anvil_generate_etch_sign_url.

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?

It gives real operational context: the default is a safe draft, and 'Use isTest=true while developing' tells the agent how to exercise the tool without side effects. It stops short of naming alternatives or stating preconditions (e.g., needing an existing organization/cast), so it is clear context without exclusions.

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