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

With no annotations, the description carries the full burden and does so well: it discloses the auth model, a Billing dependency, append-only immutability, that the reason string is customer-visible, and the currency unit. It stops short of describing the response shape or failure behavior, which is the remaining gap for a mutation.

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, each load-bearing: access scope, prerequisite, action with unit, and immutability/correction semantics. Front-loaded with the constraint that determines whether the agent should call it at all.

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 three-param mutation with no annotations and no output schema, the description covers access, prerequisite, units, side effects, and correction semantics. It omits the permitable amount range that the schema enforces and any hint about what a successful grant returns.

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 0%, so the description must compensate and largely does: it explains that amountCentavos is denominated in centavos/PHP and may be negative to reverse a prior credit, and that reason is surfaced to the customer. workspaceId is left to the UUID format in the schema, so it is not fully covered.

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 ('Credit a workspace') and immediately scopes it to platform staff acting in an account session. It is clearly distinct from the other credit-related sibling, platform_credits_list, and from platform_staff_grant, which manages staff rather than balances.

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?

Tells the agent who may call it ('Platform staff only (account session)'), the prerequisite ('Requires billing'), and how to handle a correction, steering the agent away from any edit/delete workflow by stating credits are append-only and corrected with a negative amount. This is explicit when-to-use and how-to-alternative guidance.

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