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

With no annotations, the description carries the full burden and delivers meaningful behavior: authorization is required, idempotency_key must be reused after failures, and 'accepted' means provider acceptance rather than confirmed delivery. It stops short of disclosing rate limits, permission scope, or error/retry semantics, keeping it below a 5.

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 tight sentences, each carrying distinct information, with the core action front-loaded and no redundancy or filler.

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 annotations, no output schema, and 0% schema description coverage, the description covers key behavioral traits but omits any explanation of the identity/auth parameters (address_id, read_token). It is adequate but not complete enough given the schema's silence.

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 0% across 7 parameters, so the description must compensate and it partially does: it explains the idempotency_key reuse rule and the optional reply_to_event_id behavior. It leaves address_id and read_token entirely unexplained, which is a real gap for a 6-required-parameter tool.

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?

States a specific verb and resource ('Send plain text to a verified contact') plus an optional reply mode, so the core action is unambiguous. Sibling tools are unrelated (state/event/contact management), so no explicit differentiation is needed, but the description does not name them.

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?

Provides an operational guideline ('Reuse idempotency_key after failures') and clarifies the acceptance semantics, which implies correct usage context. However, it never states when to use this tool versus alternatives or prerequisites beyond the vague 'requires user authorization'.

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