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

Beyond the readOnly/idempotent annotations, it discloses the real operational friction: the key must have no scope limits or be a person's sign-in, and an unclaimed-workspace sandbox key is refused with 403 until a person claims it. That is auth and failure-mode information an agent cannot get from the schema or annotations.

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 sentences, each carrying distinct information: what it returns, when to use it, and the prerequisites. Scope and ordering are front-loaded with 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?

For a read-only, single-parameter list tool with no output schema, the description supplies the return contents, sort order, purpose, and access preconditions. 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 single 'limit' parameter is fully documented in the schema (default 50, max 200) and the description adds nothing about it. With 100% schema coverage the baseline of 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 ('List recent delivery attempts across your workspace's webhook endpoints') plus ordering ('newest first') and returned fields. This cleanly distinguishes it from sibling list_webhooks (which lists endpoints) and ping_webhook/verify_webhook_signature.

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?

'Use it to find an endpoint that is failing' gives a concrete scenario for reaching for this tool over the others. No explicit exclusions or named alternatives, so it stops short of the 5 tier.

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