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

Annotations already declare the mutation profile (readOnlyHint=false, openWorldHint=true, non-idempotent), and the description adds genuinely non-obvious behavior: the response contains a signing secret shown only once, so the agent knows to capture and preserve it rather than discard the result. The outbound POST semantics also explain the openWorldHint in concrete terms.

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 short sentences, ordered by importance: what happens, which sibling to use instead, then the plan gate and the one-time secret. No filler and nothing buried.

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?

Covers mechanism, alternatives, prerequisites, and the shape of the return value, which is sufficient without an output schema. The remaining gap is the optional headers parameter and whether repeated calls with the same URL create duplicate destinations or error.

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 all three parameters are already documented, and the description adds only the framing that the URL is user-controlled rather than a first-party endpoint. The optional headers parameter and its use for authenticating the POST are not mentioned, so value beyond the schema is modest.

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 (add a webhook notification) and immediately explains the mechanism: each submission is POSTed as JSON to a user-controlled URL. It also explicitly separates itself from bootform_add_discord and bootform_add_slack, which is exactly what an agent needs to pick the right destination tool.

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 both the positive case (own server or any tool that accepts webhooks) and the negative case with named alternatives (use bootform_add_discord or bootform_add_slack for chat apps instead). It also surfaces a hard prerequisite — Starter plan or higher — that would otherwise only appear as a runtime failure.

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