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

Adds real context beyond the annotations: domain-admin key requirement, plan gating, and the critical fact that the API key is returned only once (a non-idempotent, capture-immediately side effect consistent with idempotentHint=false). It does not describe failure modes or what happens on name collisions, so not a 5.

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?

Three short clauses, front-loaded with the action, then constraints, then side effects, then the routing hint. No filler.

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 an irreversible-in-practice creation tool with no output schema, the description covers auth, gating, and the one-time secret return. What's missing is the response shape beyond the API key and error/conflict behavior.

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%, so the baseline is 3. The description clarifies that schema_namespace is minted server-side if omitted, but adds no new meaning for name/description/requirements beyond the schema text.

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+resource ('Create a NEW project') and the capitalized NEW plus 'Use for a fresh app' separates it from build_replace_project and build_update_project. The side effects (namespace + one-time API key) are named up front.

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?

'Use for a fresh app' gives a clear positive condition, and 'NEW' implies the boundary with replace/update siblings. It does not explicitly name an alternative tool or state when not to use it, so it stops short of a 5.

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