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

The description discloses important non-obvious behavior beyond annotations: messages are relayed without exposing the association's email, nothing is sent until the user clicks a confirmation link, the association replies directly, and unreachable associations still see that contact was attempted. This is rich, accurate context consistent with the mutation and non-idempotent annotations.

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 front-loaded with the main action and purpose, then adds prerequisites, side effects, and constraints in a compact sequence. Every sentence earns its place; there is no fluff or redundant restatement of the tool name.

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 mutation tool with no output schema, the description covers prerequisites, confirmation flow, privacy properties, failure/edge behavior, and message constraints. It gives an agent everything needed to decide when to invoke it and how to interact with the user safely.

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, but the description adds meaningful parameter context: user_email is where the confirmation link goes and where the association replies, and the message must be in the user's words as plain text. This goes beyond the schema without repeating everything mechanically.

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: 'Send a message to an association ON BEHALF of your user,' and enumerates concrete use cases (join, volunteer, ask a question, request information). It also clarifies the relay model (IA-Asso), which distinguishes this tool from read-only sibling tools and from mere record submission.

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 clearly states when the tool is appropriate and gives mandatory user-facing preconditions: ask for the user's email and explicit agreement, and warn that nothing is sent until confirmation. It does not explicitly name alternative tools or say when not to use it, so it stops short of a 5.

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