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

Annotations already declare non-readOnly, idempotent, non-destructive, so the description's job is to add operational detail — it does, with the 200-599 status range, the 0-5000 ms delay cap, the 16 KiB body limit, and the reset behavior that restores a default JSON receipt. It still doesn't say whether omitted fields are preserved or cleared on a partial update, which matters for a mutating configuration call.

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, front-loaded with the action and followed by a resettable default. The parenthetical parameter inventory is dense but every clause carries a constraint; only minor cost is that headers and delayMs are packed into a long list.

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 an eight-parameter, nested-object mutation tool with no output schema, the description covers the behavioral limits and the reset path well. The remaining gap is the update model (partial merge vs full replacement) and any auth expectations for anonymous resources, which an agent would need to call this correctly in edge cases.

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 38%, so the description carries real weight: it supplies the status range, delayMs bound, body size cap, the allowed contentType values, and the 'X- headers' prefix constraint that the schema does not express. It says nothing about the id or token parameters beyond what the schema already documents, and doesn't clarify merge-versus-replace semantics for body or headers.

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 opens with a concrete verb and object: 'Choose what a webhook inbox answers senders with', naming the resource (webhook inbox) and the effect (the reply sent to senders). It is distinguishable from siblings like create_webhook_inbox and inspect_webhook_inbox, though it never names them explicitly.

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?

Usage is only implied: you call this to configure an existing inbox's canned response, and reset:true is the escape hatch back to defaults. There is no statement of prerequisites (ownership vs token-based anonymous resources), no guidance on when to use this versus inspect_webhook_inbox or create_webhook_inbox, and no exclusions.

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