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

With no annotations present, the description carries the full burden and does disclose two real behavioral facts: the caller's own session bearer is used, and the webhooks:read scope is required. 'Fetch' implies a safe read. It stops short of error behavior (missing uuid, not-found, cross-tenant access), which keeps it below 5.

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, front-loaded with the action, then the auth mechanics. Every sentence earns its place and there is no filler or restated field documentation.

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 one-parameter read tool with 100% schema coverage and no output schema, the definition covers the essentials plus auth. The remaining gap is failure behavior for an unknown or unauthorized uuid, which an agent would benefit from knowing.

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%, and the schema itself explains that webhook_uuid is the public UUID as returned by create_webhook or list_webhooks. The description's 'by uuid' adds no syntax or format detail beyond that, so the baseline 3 applies.

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 ('Fetch a single webhook endpoint by uuid'), and the word 'single' plus the uuid requirement cleanly separates it from list_webhooks and the create/update/delete siblings. No ambiguity about what gets returned at a resource level.

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 implied: fetch one existing webhook when you have its uuid. However, no alternative is named (e.g. 'use list_webhooks to enumerate'), and no condition for picking this over list_webhooks is stated, so the agent must infer the routing.

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