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

Annotations already cover readOnly, idempotent and non-destructive, so the bar is lower; the description adds real behavioral context by noting the management token is required, that the call is free, that it does not purchase credits, and that the daily free allowance is tracked separately. It does not cover rate limits or failure modes, which keeps it from a 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?

Four short, front-loaded sentences, each carrying distinct information: purpose, safety/free status, alternative tool, and the separate free allowance. No filler or repetition.

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?

No output schema exists, but the description states what is returned conceptually (remaining purchased credits) and clarifies it excludes the daily free allowance. It could say more about the response shape or behavior for invalid/unknown hooks, but it is complete enough to call correctly.

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 100% and both parameters are fully documented with patterns and semantics in the schema, so the baseline of 3 applies. The description adds only the implicit constraint that the hook must already exist; it contributes nothing new about hookId or managementToken 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 specific verb and resource (read remaining purchased admission credits) and scopes it precisely to an existing hook via its management token. It explicitly separates paid credits from the daily free allowance and distinguishes itself from purchase_hook_credits, so an agent can tell it apart from siblings without opening schemas.

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 description clearly frames the use case (check credits, free and read-only) and routes to purchase_hook_credits for purchasing/quoting, giving an explicit when-not. It lacks an explicit trigger condition for calling this versus other read tools, so it falls just short of a full 5.

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