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

Annotations already declare non-read-only, non-destructive, non-idempotent behavior, and the description's URL-generation framing is consistent with that. It adds the supported status values but omits meaningful behavior: URL expiry, whether repeated calls issue fresh URLs, and what the caller must do with the returned URLs.

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 short sentences, front-loaded with the core action. The second sentence is somewhat redundant with the schema enum, but the overall structure is tight and wastes no space.

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. Still, for a tool whose whole purpose is handing back URLs for later use, the absence of any flow context (ordering with `thumbnail_upload`, required permissions, URL lifetime) leaves a notable gap.

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 100%, so both parameters are already documented in the schema, including the array-or-comma-string flexibility for `statuses`. The description merely restates the enum values that already appear in the schema, adding no new semantic value. Baseline 3 is appropriate.

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 and resource: 'Generate presigned upload URLs for live stream thumbnails.' This clearly separates it from a plain upload. However, it never distinguishes itself from the sibling `thumbnail_upload`, leaving the agent to infer that 'live' is the differentiator.

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?

No when-to-use or when-not guidance is given. It does not say how this relates to `thumbnail_upload`, whether it must precede an actual HTTP PUT, or what happens if `statuses` is omitted. Usage is only implied by the word 'live'.

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