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

Annotations only say this is a non-idempotent, non-destructive write; the description adds genuinely useful context beyond that — human review ('A person reads it'), no payment/account required, and a rate limit ('a few messages an hour'). That rate limit and the human-read disclosure are exactly the kind of operational facts an agent cannot get from structured fields.

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?

Two tight sentences with no filler, and the key constraints are front-loaded. The one-word opener 'Free.' is a fragment that reads slightly oddly, but it does carry real information about cost.

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 simple fire-and-forget write with no output schema and no nested objects, the description covers purpose, audience, cost, rate limit, and expected handling. Nothing essential to invoking it correctly is missing, aside from explicit guidance on the optional contact field.

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 75%, above the baseline threshold, so the schema already documents route, contact, and message. The description reinforces the message contents and implicitly enumerates the kind values ('bug, an idea, a thanks'), overlapping the enum, but adds no syntax or format detail the schema lacks.

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 a concrete action and recipient: 'Tell the people who run this service what worked, what failed or what you miss.' A 'bug, an idea or a thanks' concretely frames the resource, so there is no tautology. It does not explicitly contrast itself with the deal-management siblings, though the domain difference is obvious.

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 clear context for when this tool is appropriate (reporting a bug, an idea, or praise to the operators) and states an operating constraint: 'limited to a few messages an hour.' It stops short of naming alternatives or stating when not to use it, but no plausible conflicting sibling exists here.

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