Capture a simulator screenshot and return it as an image, using base64 over SSH to avoid a separate file-transfer step.
Capture a simulator screenshot and return it as an Image (parity with adb_screenshot).
Pipes through base64 over SSH so we don't need a separate scp step. Returns [Image, description] on success, or an error string on failure.
| Name | Required | Description | Default |
|---|---|---|---|
| host | Yes | ||
| udid | No | booted | |
| user | Yes | ||
| key_path | No |
Changes observed during successful MCP inspections.
v0.13.6Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden of behavioral disclosure. It details the transport mechanism (base64 over SSH) and the exact return format ([Image, description] or error string). It implies a read-only operation without side effects, and the parity mention adds context. However, it does not disclose potential failure conditions beyond an error string.
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 three sentences, front-loaded with the core purpose. The second sentence adds useful implementation detail, and the third specifies return values. There is no redundancy or fluff; every sentence 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?
The tool has 4 parameters, no output schema, and no annotations. The description covers the action and return format but entirely neglects parameter semantics, which is a significant gap. An agent would not know how to populate host, user, or key_path correctly without further context. The tool is only partially self-explanatory.
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 description coverage is 0%, and the description provides no information about the parameters (host, udid, user, key_path). It does not explain their meaning, required format, or how they are used. The agent must rely solely on the schema titles and defaults, which are insufficient for correct invocation.
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 tool's purpose: capture a simulator screenshot and return it as an Image. It explicitly references parity with adb_screenshot, which distinguishes it from the Android counterpart and clarifies it targets iOS simulators. The verb 'capture' and resource 'simulator screenshot' are specific and unambiguous.
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?
The description implies usage context by mentioning parity with adb_screenshot, suggesting it is the iOS equivalent, but it does not explicitly state when to use it versus alternatives. It also omits prerequisites like SSH connectivity or simulator boot state. No explicit when-not-to-use guidance is provided, leaving some inference required.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.