FREE. Expand one step of an emit_app recipe: the full instruction, why it matters, how to know it worked, and what to do when it did not. emit_app returns steps in short form to stay inside the response budget — call this before any step you are not completely sure about. Needs the same share code and the step's id.
| Name | Required | Description | Default |
|---|---|---|---|
| appId | Yes | the share code you passed to emit_app | |
| stepId | Yes | the step id, e.g. "configure" or "write" |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden and fully discloses the tool's action: expanding a step with full instruction, rationale, success criteria, and failure handling. It clearly implies a read-only informational retrieval with no hidden side effects.
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 description is mostly efficient and front-loaded with the action, but the leading 'FREE.' is extraneous and adds no value. Otherwise, all sentences contribute meaningful usage and behavioral detail.
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?
Given the tool's simplicity and the rich sibling context, the description sufficiently explains what the tool does, when to use it, and what information it returns. No additional context is needed for 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?
Both parameters are described in the schema with concrete examples, and the description adds useful context by noting appId is 'the share code you passed to emit_app'. This fully clarifies the meaning and relationship of the inputs.
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 clearly states the verb 'Expand' and the specific resource 'one step of an emit_app recipe', distinguishing it from sibling tools like emit_app and get_component. It also explains the tool's purpose relative to emit_app's short-form steps.
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 explicitly says to call this tool 'before any step you are not completely sure about', providing direct when-to-use guidance. It also references emit_app's behavior to establish context, making the usage criteria unambiguous.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.