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

Annotations already declare mutation (readOnlyHint=false), idempotence, and non-destructiveness, so the bar is lower. The description adds two facts the annotations cannot convey: the reply is publicly visible on the page, and the operation deliberately does not alter approval state. It stops short of noting the 280-char limit or whether unapproved supporters can be replied to.

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 short sentences, no filler, with the action stated first and the exclusion second. Every clause carries information.

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?

An output schema exists, so return values need no explanation, and annotations cover the safety profile. For a 2-param mutation the description is nearly sufficient; only the meaning of 'id' and the public-visibility consequences on unapproved supporters are left implicit.

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 only 50% — the 'reply' parameter is documented, but the required 'id' is not. The phrase 'beside a supporter' weakly implies id is a supporter id (versus goal/page/support ids used by many siblings), but this is inference, not specification. Baseline 3 with partial compensation.

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 pair (write/change) and a concrete resource (the public thank-you shown beside a supporter), and explicitly draws the boundary against the approval siblings with 'Does not approve them.' An agent can separate this from approve_support/reject_support without opening a schema.

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?

Gives a clear negative condition ('Does not approve them'), which routes the agent away from the approval workflow, but never names an alternative tool or states a positive trigger (e.g. 'use when you want to respond to an already-approved supporter'). Clear context with no explicit alternatives.

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