ae_capture_frame

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

With no annotations provided, the description carries the full behavioral burden. It adds useful context: the output is a PNG, it is returned as an image 'when possible', and it defaults to current CTI. But it leaves key traits undisclosed, such as whether the operation mutates anything, what happens when returning an image is not possible, and whether rendering is expensive or blocking.

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 two sentences with no filler. It front-loads the core operation first, then adds the usage trigger and default behavior. Every clause 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 is moderately complex and has no output schema, so return behavior matters. The description says a PNG image is returned 'when possible', but not what is returned when that is impossible, nor how composition selection works when both comp_name and comp_index are omitted. Since all parameters are optional, this is a material 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 description coverage is 100%, so all four parameters are already documented in the schema; the baseline is 3. The description only restates the time behavior ('defaults to current CTI time'), which duplicates the schema's 'default current time', and adds no new parameter-level meaning.

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 names the action (render a still PNG), the resource (a composition), and the key parameter (time in seconds), which is more specific than the tool name alone. However, it does not distinguish itself from the sibling ae_capture_frames, so it does not fully meet the sibling-differentiation bar for a 5.

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 explicitly tells the agent when to use the tool: after visual changes, so it can verify the result. The mention that it defaults to current CTI also signals it can be used for quick checks without arguments. It does not, however, contrast with ae_capture_frames or ae_render_composition, so exclusions are missing.

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