deploy_appDeploy a completed PromptUI build to a live URL. The first deploy of each app is charged; redeploying that same app is free. If publishing a new app needs a plan, the tool returns how to start the Build free trial instead of deploying.
| Name | Required | Description | Default |
|---|---|---|---|
| buildId | Yes | The buildId of a completed build | |
| _confirmed | No | Set to true only after the user has explicitly approved this exact write or credit-spending action. |
Changes observed during successful MCP inspections.
Input schema / properties / _confirmedAdded value: +{
+ "default": false,
+ "description": "Set to true only after the user has explicitly approved this exact write or credit-spending action.",
+ "type": "boolean"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond the annotations (openWorldHint=true, idempotentHint=true, destructiveHint=false), the description discloses the cost model — first deploy charged, redeploys free — and a non-obvious failure path where the tool returns free-trial instructions instead of deploying. It omits that a `_confirmed` user approval is required for this credit-spending write, which the schema covers but the prose does not reinforce.
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 tight sentences with no waste: what it does first, the cost consequence second, the plan fallback third. Every sentence earns its place and nothing repeats the schema verbatim.
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 covers the main non-success return (trial instructions instead of a deploy) and the prerequisite, which is what an agent needs to avoid misusing it. Only the confirmation requirement for spending credits and the shape of a successful response (the live URL) are left implicit via the title.
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% and the buildId description already specifies 'a completed build,' so the schema carries the parameter burden. The description's reference to 'a completed PromptUI build' adds only marginal reinforcement and says nothing about `_confirmed`.
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 first sentence gives a specific verb and resource: 'Deploy a completed PromptUI build to a live URL.' The 'completed build' prerequisite implicitly separates it from build_app, though no sibling is named explicitly.
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?
Usage is implied by the 'completed build' qualifier and the plan/trial fallback phrasing, but the description never names build_app or another alternative, nor does it state exclusions such as what to do if the build is incomplete.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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