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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds real value beyond them: deterministic output, the specific artifacts returned (subject, body, mailto, X intent URL, SHA-256), and confirmation that nothing is sent. It does not describe failure behavior when validation against contact.json fails, which is the main remaining gap.

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 tight sentences, all front-loaded with the core action first and constraints after. The opening sentence duplicates the title verbatim, which is minor redundancy, but nothing else is wasted.

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 11-parameter, nested, no-output-schema tool, the description covers return values, determinism, validation, and permission scoping well. Missing only error/failure semantics, which keeps it from a 5.

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?

With 64% schema coverage across 11 parameters (including a nested sender object and two enums), the schema carries most of the semantics. The description adds no parameter-level guidance beyond naming output fields, so the baseline 3 is appropriate.

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 ('Draft a correction or question... as an email and X post without sending it') and explicitly names the non-action (no sending). The title and description combine to make it unmistakable against siblings like verifyApprovedAction or fetch.

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?

Explains the flow clearly: draft, validate, return artifacts, and 'Sending is up to the caller and requires its principal's permission.' It also equates the tool with the underlying endpoint. It stops short of naming when to prefer this over another sibling, but the surrounding context is sufficient for correct selection.

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