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

The readOnlyHint annotation already establishes this as a safe read, but the description adds real value by disclosing the return contents (URL, event types, channels) and the underlying REST route. This is meaningful behavioral context absent from structured fields, though nothing is said about auth scoping or error behavior.

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 sentences, front-loaded with the action and payload scope, followed by a compact API reference. No filler.

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?

With no output schema, the description usefully enumerates the returned fields, and annotations cover the safety profile. It is nearly complete for a two-param read tool; only auth/scope notes are 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?

Schema description coverage is 100%, so both app_id and endpoint_id are already documented in the schema. The REST path in the description reinforces where each id sits, but adds no new format or constraint detail beyond the schema.

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 precise verb and resource ('Fetch a single webhook endpoint') and immediately scopes the payload ('including its URL, subscribed event types and channels'). This clearly separates it from svix_list_endpoints and svix_get_endpoint_stats without the agent needing to open a schema.

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 word 'single' implies the lookup use case versus the list sibling, but the description never states when to prefer this over svix_list_endpoints or what prerequisites apply. Usage is inferable rather than stated.

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