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

With no annotations, the description carries the behavioral burden and discloses key traits: creates a pending workspace, sends a code to email or US phone, is idempotent on idem_key, and gates on terms acceptance. It still omits failure behavior and response details, but the core mutation and idempotency semantics are present.

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-loads the signup action, then the code flow, then the terms requirement. The "FIRST" instruction appears last, which is slightly awkward, but every sentence adds needed flow information.

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 complex signup tool with no output schema and no annotations, the description covers the essential workflow, terms gating, idempotency, and the next tool to call. It lacks return-value and error-case details, but the operational essentials are present.

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 schema already documents the parameters. The description adds useful semantics beyond the schema: email is preferred over phone, idem_key makes retries safe, and accept_terms must only be true after explicit user acceptance.

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 uses a specific verb and resource: "create a pending workspace and send a 6-digit code." It clearly frames this as the signup step and names verify_phone as the next action, so an agent can distinguish it from sibling tools like verify_phone or describe_product.

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 an explicit sequence: ask for the code, then call verify_phone. It also states the prerequisite of showing Terms of Service and Privacy Notice and passing accept_terms: true only after acceptance, which is unambiguous when-to-use guidance.

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