pix_recapture_playback

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

Annotations already declare idempotentHint=true and destructiveHint=false, and the description adds context beyond them: the operation is scoped to the open capture and requires pixtool to be launched. However, readOnlyHint=false signals a mutating operation, and the description doesn't disclose what side effects 'capturing a replay' has (e.g., writing a file or changing the open capture).

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 a single front-loaded sentence with no wasted words, stating the action before the prerequisite. The parenthetical compresses the pixtool prerequisite without explaining why it matters, but overall the structure is efficient.

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?

While the output schema covers return values and annotations cover the safety profile, the tool has 4 parameters at 0% schema description coverage and the description leaves most of them unexplained. It also doesn't clarify what a 'replay' is or what the tool concretely produces, which is a significant gap for a non-read-only operation.

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%, so the description carries the full burden of explaining the 4 parameters, but it only weakly hints that capture_id refers to an open capture. It says nothing about expand_execute, timeout_seconds, or include_recreation, leaving the agent to guess their 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 states a specific verb ('Capture') and resource ('a replay of the open capture'), which distinguishes it from siblings like pix_perform_playback (performing playback) and pix_recapture_region (recapturing a region). However, it doesn't explicitly contrast with those siblings, and 'capture a replay' remains somewhat ambiguous about what output is actually produced.

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 parenthetical 'pixtool must itself be launched for capture' provides a concrete prerequisite that helps the agent judge whether the tool can run in the current environment. But there is no guidance on when to choose this over pix_perform_playback or pix_recapture_region, and no exclusion criteria are given.

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