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

The annotations already declare this is a non-read-only, non-destructive, non-idempotent mutation, so the safety profile is covered. The description adds real value by disclosing the downstream side effect (main-video uploads trigger transcript, shot and silence indexing), but it omits the consequence of the non-idempotent hint — e.g., that repeating a finish with the same storage_key may fail or duplicate — and says nothing about orphaned/incomplete uploads.

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?

Two sentences, front-loaded with the action and followed by the downstream effect; nothing is redundant or padded.

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 an 8-parameter mutation with no output schema, the description covers what happens after success only in terms of analysis being kicked off. It does not say what identifier is returned, whether analysis is asynchronous, or what the caller should do next (poll index_status / wait_for_job), leaving a meaningful gap for an agent chaining calls.

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 63%, so the schema already documents role, parts, upload_id and duration_s. The description only reinforces that project_id is an explicit target rather than the navigation pointer, which the schema text already says; it adds no meaning for kind, multipart parts/upload_id, or how filename and duration_s interact with probing.

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 pair (completes / registers) and the resource (a previously prepared storage upload), and scopes the result to the explicit project. The phrase 'previously prepared' signals it is the second half of a two-step flow, though it never names the upload_start sibling outright.

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?

Usage is only implied: the agent must infer that this runs after an upload has been prepared (presumably via upload_start) and never gets explicit when-not guidance, such as what to do for multipart versus single-part uploads or how it relates to insert_media for already-hosted assets.

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