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

Annotations already declare readOnlyHint=true, so no mutation warning is needed. The description adds meaningful behavioral context by disclosing support for 20 providers, which tells the agent the provider parameter is constrained and not arbitrary. This goes beyond the schema's examples and helps clarify expected usage.

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?

The description is two sentences, front-loaded with the core operation and followed by a provider list. Every phrase adds value: the verb-resource pair defines the action, and the provider list signals supported ecosystems. No redundant restatement of schema properties or annotations.

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?

The description is adequate for basic invocation but leaves gaps. It does not specify what the tool returns (e.g., a boolean, a result object) which matters for a verification tool, and the provider list is partial ("including...") without enumerating all 20 valid options. The schema covers requestUrl's conditional requirement for Twilio/HubSpot, but the description alone would not make an agent aware of this nuance.

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 description coverage is 100%, so each parameter is already documented in the schema (body, secret, headers, provider, requestUrl). The description adds no extra parameter-level semantics, such as format or edge cases, beyond mentioning the secret and provider support. Baseline 3 is appropriate when the schema carries the explanatory weight.

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 specific verb and resource: 'Verify a webhook signature against a secret.' This clearly distinguishes it from siblings like anyhook_inspect or anyhook_mock, which serve different purposes. The provider list also adds scope, making it evident this is a verification tool, not a general webhook utility.

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?

The description implies when to use the tool (to validate webhook signatures) but does not explicitly compare it to alternatives or state when not to use it. Siblings like anyhook_inspect or anyhook_replay are related, yet no routing guidance is offered, so the agent must infer the tool's niche solely from its verb.

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