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

Goes well beyond the annotations (readOnlyHint=false, destructiveHint=false, openWorldHint=true) by disclosing that credits expire at midnight local time on the set date, that the reason is persisted on the account, that confirmation is on by default and configurable, and that the action reaches other people. It also names the required API key scope.

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?

Purpose is front-loaded in the first sentence and the paragraph builds logically. It is somewhat dense and the confirmation/API-key sentences read like generic platform boilerplate, but nothing is materially wasteful.

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 mutation tool with no output schema, the description covers prerequisites (active credit type), temporal semantics of expiry, persistence of reason, confirmation behavior, cross-user impact, and auth requirements. An agent has enough to invoke it 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%, giving a baseline of 3, but the description adds meaning the schema does not: credit_type must be active in the studio, expires_on resolves at midnight local time, and reason is saved on the account. These clarify constraint and side-effect semantics of specific parameters.

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 — adding complimentary credits of one credit type to a customer's account — and ties it to a recognizable UI action ('Give Credits on the Credits tab in Admin'). It is clearly distinguishable from read-only siblings like mariana-tek_list_customer_credits.

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?

Provides real context for when to use it, including the precondition that the credit type must be active in the studio, and gives confirmation guidance for a side-effecting call. It stops short of naming sibling alternatives or explicit when-not-to-use conditions, so it is strong but not exhaustive.

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