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

Annotations already cover the mutation/idempotency safety profile (readOnlyHint=false, idempotentHint=true). The description adds real behavioral constraints not in annotations: a 0.1–6-second duration window, a 32 non-overlapping-edit cap per project, and that samples are in source sample_rate units. It does not describe what record is produced or any rate-limit/permission behavior, keeping it below a 5.

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?

Very short and front-loaded, leading with the core action and scope before the constraints and the follow-up pointer. The unusual line breaks and indentation hurt readability slightly but no sentence is wasted.

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?

An output schema exists, so return values need not be explained, and the key creation constraints (duration, count cap, unit basis, follow-up step) are present. The main gap is any guidance on idempotency_key usage or project scoping, which is minor for this level of complexity.

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% across 4 required params, so the description must compensate. It clarifies the unit and range semantics of start_sample/end_sample (source sample_rate, zero allowed, 0.1–6s span) but says nothing about project_id or idempotency_key, leaving half the contract to be inferred from names and patterns.

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+resource ('Save a 0.1–6-second selection') and immediately scopes it against a sibling action ('not a paid generation'). An agent can tell this apart from generate_changes and knows it is the edit-creation entry point.

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 clear context for when to call it (creating a selection edit) and explicitly names the follow-up tool: 'Next set original/corrected and replacement words with update_edit.' No explicit when-not guidance beyond ruling out paid generation, so it falls 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.