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

Annotations already declare this is a destructive, non-idempotent, open-world write, so the safety profile is covered. The description adds genuinely useful behavior the annotations don't: the credit effect on the user's balance and the per-user-per-code rate limit. It omits error behavior for invalid, expired, or already-redeemed codes, keeping it out of 5 territory.

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, both carrying weight: the first states action, source example, effect, and limit; the second states the trigger. The action leads and nothing is repeated from the schema or annotations.

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 one-parameter mutation with full annotation coverage and no output schema, the description covers action, effect, frequency limit, and call trigger. The remaining gap is failure handling — what to tell the user when a code is invalid or already redeemed — which an agent would have to discover at runtime.

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 the schema already documents the single `code` parameter including case-insensitivity, so the baseline is 3. The description adds provenance context ("e.g. one shared at a XeoRank workshop") that helps the agent recognize what a valid code looks like, a modest but real addition.

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 ("Redeem an Assist credit coupon code") plus the observable effect ("adds credits to the user's balance"). No sibling tool does anything similar — assist_balance and assist_savings are read-oriented — so an agent can select this without ambiguity.

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 an explicit trigger condition ("If the user mentions having a code, redeem it for them") and a constraint ("Once per user per code"). It stops short of stating when NOT to call it or naming the alternative for balance/credit questions (e.g. assist_balance), but the positive routing is unambiguous.

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