Keystroke Overlay

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

Annotations already flag destructiveHint=true and non-idempotent writes, so the safety profile is covered. The description adds genuinely non-derivable behavior: it never renders typed text because the log contains none, which prevents an agent from expecting keystroke content and explains a privacy-relevant constraint.

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?

Two sentences, zero filler, with the core action front-loaded and the prerequisite and privacy constraint trailing efficiently. Nothing could be removed without losing information.

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 an output schema present, return values need not be explained, and the description covers purpose, prerequisite, and the no-typed-text guarantee. The main residual gap is routing guidance against the other visual-overlay siblings, which keeps it from a 5 for a 13-parameter tool.

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% and all 13 parameters are documented inline (keys modes, size, lingerSec, overwrite, etc.), so baseline is 3. The description only adds the events-log prerequisite, which is useful linkage but not parameter-level 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 ('Burn keycast-style badges') and resource (shortcuts, clicks, typing) sourced from the recording's input event log, which cleanly separates it from sibling overlay/callout/cursor tools. The parenthetical about start_recording events: true further pins down what it operates on.

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 the essential precondition — the recording must have been made with start_recording events: true — which is a real gating condition an agent needs before calling. It stops short of naming alternatives (e.g., overlay or cursor) or when NOT to use it, so it falls just short of a 5.

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