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

With no annotations, the description carries the full burden of behavioral disclosure. It clearly states that the deletion is idempotent (deleting a non-existent file is not an error) and that it refuses to delete recordings that are still being written. These are non-obvious behaviors that help an agent understand side effects and failure modes, though it could also mention what happens on refusal (e.g., error vs. no-op).

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 sentences, each with a distinct purpose: the action, the input source, and two key behavioral constraints (idempotency and refusal condition). No fluff; the most important information is front-loaded.

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 single-parameter, idempotent delete operation with no output schema, the description covers the essential context: what it deletes, where the input comes from, and the critical precondition (stop first). It does not describe the return value or error handling, but that is a minor gap given the simple nature of the operation and the behavioral clues already provided.

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 schema already documents httpPath with an example. The description repeats the source ('httpPath returned by ios_record_stop') but adds no new meaning; it merely echoes what the schema says. Thus the baseline of 3 applies.

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 ('Delete'), a precise resource ('finished iOS recording mp4 from disk'), and clarifies the input source ('httpPath returned by ios_record_stop'). This clearly distinguishes it from general file deletion tools like ios_file_delete and from recording start/stop tools like ios_record_start/stop.

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 explains exactly what input to pass and from where ('Pass the httpPath returned by ios_record_stop'), and includes a clear precondition: 'call ios_record_stop first' for recordings still being written. It does not explicitly name alternative tools to consider, but the context is unambiguous enough for an agent to select it for cleaning up finished recordings.

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