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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds valuable context about what the contract contains (headers, payload, retry semantics, etc.) and that it's free, which is not in the annotations. However, it does not disclose any potential side effects (there are none) or rate limits, which are not critical given the read-only nature.

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 a single, dense sentence that front-loads the core purpose and lists the contract components without fluff. It is efficient and earns its length, though it could be broken into two sentences for readability. The 'Free.' note is a minor addition. Overall, it is concise and structured.

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 no-parameter, read-only documentation tool with an existing output schema (indicated by 'Has output schema: true'), the description is complete. It states when to use, what the contract covers, and the cost implication. Nothing an agent needs to call it correctly is missing.

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?

The tool has zero parameters, so the baseline is 4. The description does not need to explain parameters, and the schema coverage is 100% trivially. It does add context about the returned content, but that is not parameter semantics. Thus a 4 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?

The description states a specific verb ('Returns') and a clear resource ('the custom webhook contract an endpoint must implement to receive BlogSEO articles'), listing the key elements (headers, payload, multi-language, retry semantics, secret verification, etc.). It clearly distinguishes this from sibling tools like connect_custom_webhook and test_custom_webhook by focusing on the specification of the contract.

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 explicitly instructs the agent to 'Read it before writing or reviewing a webhook receiver,' which is a clear when-to-use directive. It also notes the tool is free, removing any cost concern. No exclusion or alternative is necessary since this is the definitive source for the contract.

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