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

Annotations already mark this as a non-readonly, non-destructive, non-idempotent operation, and the description adds a lot beyond that: result links expire after 1 hour, the file is downloaded from download_url, held in R2 during the job, processed via a headless browser, and the input copy is deleted at job end. It doesn't cover auth, quotas, or failure behavior, which keeps it from 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?

The primary behavior is front-loaded in the first sentence, followed by input requirements, optional settings, return behavior, and pipeline details. Every sentence carries information, though the R2/headless-browser processing chain is longer than most callers need.

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 no output schema, the description correctly explains that download links are returned and expire in an hour, and it documents the full input lifecycle. The remaining gap is the free-form settings object, whose mode and fade semantics are named but never defined in either schema or description.

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 echoes the schema's settings fields (startSec, endSec, mode, fade) and adds only a minor qualifier that outputFormat/bitrateKbps apply 'where the tool supports them'; it supplies no units, ranges, or allowed mode values for the free-form settings object.

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 names a specific verb and resource and scope: 'Cuts an audio file down to a start and end time, or removes that section,' which cleanly separates it in concept from siblings like fade_in_out, silence_remover, or audio_splitter. It stops short of explicitly routing the agent away from those near-neighbors, which is what a 5 would require.

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?

It states the input precondition ('one file with a public HTTPS download_url'), which is genuinely usable context, but gives no explicit when-to-use/when-not guidance and never names an alternative tool. Usage is inferable from the trim semantics rather than stated.

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