get_frame

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

No annotations are provided, so the description carries the full burden; it discloses two useful traits beyond the schema — output is a full-resolution image, and it works over MCP without filesystem access. It does not describe failure modes (invalid index, missing recording), which keeps it short of 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 sentences, front-loaded with the core purpose, then the when-to-use contrast, then the call shapes. Nothing is redundant and no filler is present.

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 and no annotations, the description still covers what the tool returns (an image at full resolution), how to invoke it two ways, and where the argument values originate. Only error/edge-case behavior is unaddressed.

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 already 100%, so the baseline is 3, but the description adds real value by explaining the two alternative call shapes and confirming that `dir` and `index` come from the `record` response. It stops short of adding format or validation detail beyond the schema.

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 and resource ('Return a single frame from a prior recording at FULL RESOLUTION, as an image') and explicitly contrasts it with the downscaled contact sheet produced by `record`. An agent can distinguish this from siblings like capture and record immediately.

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 trigger condition: use this 'when it is too small to read fine detail or small text' from the contact sheet. It also names both invocation modes (dir + index, or direct path) and where to obtain those values from the `record` response.

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