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

Adds real behavioral context beyond the annotations: 'No charge here' clarifies the billing posture of a non-readOnly tool, the response shape (total in credits plus projectId) is spelled out, the kit zip contents are disclosed, and repeat-call behavior is confirmed. Only the idempotency note restates what idempotentHint already says.

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?

The key fact ('No charge here') is front-loaded, and the four sentences each add information: cost, scope, return values, and follow-on workflow. It is dense but nearly every clause earns its place.

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?

With no output schema, the description correctly compensates by describing the return values (credits total, projectId, zip contents) and the downstream workflow. Only the input parameter's semantics remain under-specified.

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?

The single specId parameter has 0% schema description coverage, so the description carries the burden. It repeatedly frames the input as a 'saved spec' whose style is matched and whose files are included, which implies what specId points at, but it never states the ID format or that it must be an existing saved spec.

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 concrete action (plans the assets a saved spec needs), enumerates the asset types produced (GUI set, icons, thumbnail, props, music), and names the outputs (a credit total and a kit projectId). It is clear enough to separate from siblings, though it only implies the distinction from plan_kit rather than stating it outright.

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 workflow: show the user the total, then draft/approve/generate on the returned projectId 'exactly as after plan_kit', noting generate takes confirmCredits. It also tells the agent that repeat calls return the same project. It stops short of saying when NOT to use this versus plan_kit or game_concept.

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