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

The annotations already mark the tool destructive, but the description adds operation-level consequences: create sends no invitations, and changing an unverified channel invalidates old links/OTPs. These are non-obvious side effects that materially change how an agent should plan follow-up actions.

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?

Three dense sentences front-load the primary create/update distinction, then add the critical destructive side effect and the follow-up condition. There is no filler, repetition, or unnecessary restating of schema contents.

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 key operation split, duplicate avoidance, destructive side effects, and follow-up timing, while the schema supplies the detailed parameter and verification rules. The main gap is that the description does not state what the tool returns, which is more noticeable because there is no output schema.

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%, and the schema itself documents parameters with useful details like E.164 normalization, digits-only CPF/CNPJ, and the verification-integrity constraint on email/whatsapp updates. The description adds behavioral context but does not add parameter-level meaning beyond what the schema already provides.

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 concrete actions: 'create adds a workspace contact without sending invitations' and 'update corrects a shared contact subject to Assinafy's verification restrictions.' This makes the tool's purpose clear and distinguishes the create and update modes from each other and from the find_signers sibling.

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 explicitly instructs the agent to 'find_signers first to avoid duplicates' before creating, and it conditions follow-up on both a successful correction and user authorization for a reminder. This is prescriptive when-to-use and when-not-to-use guidance tied to real workflow steps.

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