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

Annotations already mark this as non-read-only, non-destructive, non-idempotent. The description adds meaningful context beyond them: PROJECT-SCOPED to the explicit project_id, returns the project identity with its result, and preserves the sound identity and loudness (only timing changes). It omits permissions/rate-limit behavior but adds real behavioral value.

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?

Front-loads the PROJECT-SCOPED constraint and the core action before detail. The final sentence defining `at` is dense and convoluted but every sentence carries information rather than filler.

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 3-param mutation tool with no output schema, it covers scope, the id source, the `at` semantics, and what is returned (project identity). Nothing critical is missing, though a note on non-idempotency or repeat-call behavior would round it out.

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 coverage is only 33% (project_id documented), so the description must compensate, and it does: `id` is sourced from get_edl and `at` is explained at length via add_sfx's hit-vs-start distinction. Only minor gaps remain (no numeric format/unit hints for `at`).

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 ('Retime an existing sound effect') and immediately anchors it with a concrete example ('the whoosh is too early'). The clause 'Keeps which sound and how loud' scopes it precisely against add_sfx/remove_sfx, so an agent can distinguish it without opening a schema.

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: use it to retime an *existing* sfx, and it points to get_edl as the source of `id`. It references add_sfx to explain the `at` semantics, but never names an explicit when-not or a preferred alternative, so guidance is clear but lacks exclusions.

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