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

Beyond the annotations (non-readonly, non-idempotent, non-destructive), the description discloses genuinely useful behavioral facts: the returned key's clear value is shown once and is not recoverable afterwards, and the call requires project Admin. That secret-handling and authorization context is exactly what annotations cannot carry.

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 action and the critical one-time-secret warning, and every sentence carries information. The phrasing ("never paste it anywhere but back to them") is slightly verbose but earns its place as a security constraint.

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 two-parameter create tool with no output schema, the description covers the essential gaps: admin permission, project-slug defaulting, and one-time secret visibility. Minor omissions (key format, per-project key limits) are not significant enough to block correct invocation.

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 50%: the `project` parameter is documented in the schema, while `name` is not. The description only implies that `name` is the key's label and largely repeats the project-slug rule already in the schema, so it adds marginal meaning over the structured fields.

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?

The description gives a specific verb and resource ("Mints a project key") plus the attribution behavior and a mapping to the API keys › Create key operation. It does not explicitly distinguish itself from siblings like revoke_api_key or list_api_keys, so it lands just short of a 5.

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?

It states a prerequisite ("needs project Admin") and a conditional parameter rule ("Name the project by slug; omit it when the organization has one live project"). It stops short of naming alternatives or when-not-to-use cases, so it is clear context without explicit exclusions.

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