reframe

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

With no annotations, the description carries the full load. It does disclose useful behavior beyond the schema: that focusX/focusY only bias the crop in crop mode, and that "follow" invokes an optional, lazily-loaded face detector, hinting at added latency. It omits that this is a compute-heavy write operation producing a new file, and says nothing about output overwrite semantics or failure modes.

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 the verb, targets and mode list front-loaded. Minor redundancy: the mode enumeration restates the schema enum and the per-parameter mode descriptions, so a few words could be cut.

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?

For a 10-parameter tool with no annotations and no output schema, the description covers modes, crop focus and subject tracking adequately, and the schema fully documents defaults and ranges. It leaves the write-side story (overwrite behavior, cost of processing long videos) unaddressed, which is the main remaining gap.

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%, so the baseline is 3, but the description adds interaction semantics the schema's per-field text does not: focusX/focusY are gated to crop mode, and "follow" is a time-varying subject tracker rather than a static offset. That crossover context is genuine added value.

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 ("Reframe a video") plus the exact target aspect ratios and the three supported modes. No sibling (trim, cut, compose, render) does reframing, so an agent can route here decisively without opening the schema.

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 establishes the default mode ("centered crop (default)") and mode-specific constraints, which helps pick a mode, but it offers no guidance on when to choose reframe over siblings like render or compose, nor any prerequisites. Usage is implied rather than stated.

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