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

No annotations were provided, so the description carries the full burden. It explicitly discloses that the action is performed live on the device, that replacing appLaunch step (index 1) is rejected, and that it shares action params with flow_recording_action. A minor gap is it doesn't state return format or failure behavior if the recording isn't running.

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?

Four sentences, all informative. Each sentence earns its place: the operation description, the live-execution caveat, the use case, the appLaunch restriction, and the param cross-reference. No padding or repetition.

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 complex tool with 15 params and no output schema, this description is highly complete. It covers the key behavioral constraints (live execution, appLaunch restriction, in-place overwrite), the relationship to sibling tools (flow_recording_action, flow_recording_delete_step, flow_recording_save), and points to the shared param contract. Schema covers all params so no missing parameter documentation.

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 the baseline is 3. The description adds context about stepIndex being 1-based (in schema) and that action accepts the same params as flow_recording_action, but doesn't add meaning beyond what the schema already documents for most parameters. The 'same action params' cross-reference is helpful but the schema already covers all parameters in detail.

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 uses a specific verb+resource ('Replace one step of an in-progress recording') and clearly states what happens: performs the action live then overwrites the step at stepIndex instead of appending. It distinguishes from flow_recording_action by explaining the difference (overwrite vs append) and explicitly names the sibling tool.

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?

Provides excellent when-to-use guidance: 'Use this to fix a mis-recorded step... in place rather than deleting + re-recording + reordering.' It also names the alternative behavior (flow_recording_action) and the timing constraint (before flow_recording_save). This exceeds typical guidance.

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