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

With no annotations, the description carries the full burden and does a lot: it discloses the refusal condition for closed projects, the visibility tier of each field (worktree/task public, ownerContext members-only, publicContext public-safe only), and that validation failures are reported back ('The answer says so when what you sent is not in it'). It does not cover auth scope beyond the API key, retryability, or what the created upload returns.

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 description opens with a long locale/translation preamble rather than what the tool does, and the operationally critical fact (uploads are currently refused) lands near the end. Every sentence is substantive, but the ordering is not front-loaded and the language rules are verbose.

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 9-parameter mutation tool with no annotations, no output schema, and only 56% schema coverage, the description supplies the missing operational context: refusal state, field visibility, locale requirements, and a caution against unsolicited recording. The main remaining gap is the return value / upload handoff, which nothing else documents.

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?

At 56% schema coverage, the description adds real meaning beyond the schema by specifying which fields must be written in English (title, taskName, ownerContext, publicContext), how worktreeName must be left as the checkout directory name, and the audience/visibility semantics of the context fields. It says nothing about filename, mimeType, or byteSize, which the schema covers.

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 third sentence names a specific verb and resource: 'creates a direct R2 upload for an MP4 or WebM recording, filed under the project this API key belongs to.' That is concrete and distinguishable from siblings like complete_video_upload or list_videos, though the description never explicitly contrasts itself with them, and the purpose is buried behind a long writing-conventions preamble.

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 gives explicit when-not guidance ('This project is currently closed to new recordings: create_video_upload will be refused...') and a strong precondition ('Do not record a session to upload here — ask the person you are working with first'). It does not name the natural follow-up sibling (complete_video_upload) or explain the multi-step upload flow, so it stops short of full routing guidance.

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