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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world). The description adds genuinely non-derivable behavior: polling semantics and the important caveat that signed observations attest relay attempts, not successful business processing by the receiver. That semantic limit is exactly the kind of context annotations cannot express.

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?

Four short sentences, front-loaded with the core action and the key read/poll distinction. Each sentence carries non-redundant meaning (scope, usage, semantic caveat, no-side-effect guarantee), though the phrasing is slightly dense.

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 3-parameter tool with no output schema and strong annotations, the description covers the important ground: what it reads, when to call it, the statuses it resolves, and the limit on what a signed observation proves. Return-field detail is absent, but with 100% schema coverage and rich annotations that is a minor gap.

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 token, hookId and deliveryId are already fully documented in the schema, including pattern constraints and the note that acceptance does not mean delivered. The description restates deliveryId and the token but adds no syntax or format detail beyond the schema, so 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?

The description states a specific verb and resource: read one accepted event keyed by deliveryId plus hook token. It distinguishes itself from accept_hook_event by positioning itself as the follow-up read/poll step, so an agent can tell the two apart without touching either 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?

It gives clear usage context: poll after accept_hook_event to distinguish queued, retried and completed deliveries. It also rules out side effects ('No new delivery or payment'). It stops short of naming an explicit alternative sibling (e.g. verify_hook_receipt) or when not to use it, so it is clear context but not full routing guidance.

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