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

Goes well beyond the annotations (destructive/idempotent/openWorld) by disclosing the human-gated elicitation requirement, that elicitation-incapable clients are refused while dry_run works anywhere, and that a revoked tombstone is written even for never-invited addresses and survives later bulk re-invites. The only gap is what a successful response looks like or how refusal surfaces to the agent.

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?

Front-loaded with the core action and scope before the caveats. It is a dense single paragraph — long, but nearly every clause carries operational information (gating, tombstone persistence, irreversibility, sibling routing); minor trimming of the delete_coupon justification would tighten it.

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, and the description covers the complex parts an agent needs: write gating, tombstone semantics, irreversibility for redeemed invites, and prerequisite listing. Missing the `reason` field's purpose and any indication of the return/refusal shape keeps it short of complete.

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 0%, so the description carries the burden; it clarifies that email is the targeted address, code is the coupon, and that dry_run changes the gating behavior. However `reason` is never mentioned and `app_id` is never explained, leaving two of five parameters undocumented in both schema and description.

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 — 'Withdraw one address's right to spend a coupon' — and immediately characterizes it as 'the targeted block,' which distinguishes it from whole-coupon deletion. An agent can tell exactly what object is affected and at what granularity.

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?

Gives explicit routing: prefer over delete_coupon when a single recipient misbehaves, because deleting punishes other invitees; call list_coupon_invites first to see status. It also states the boundary condition — it only blocks FUTURE redemptions, and an already-`redeemed` discount must be handled via dashboard cancel/refund.

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