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

Annotations already establish the safe, idempotent, closed-world read profile, and the description adds real context on top: deterministic ordering (oldest first), an inventory of the fields returned (who asked, status, resulting version), and an explicit cost statement (free, no credits). It does not mention pagination or result-size limits, which keeps it short of 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?

A single front-loaded sentence carries the scope, ordering, and returned fields, followed by a short cost tag. It is dense but every clause earns its place; the enumerative run-on is the only mild readability cost.

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 one-parameter, read-only tool with an output schema, annotations, and full schema coverage, the description supplies what structured data cannot: ordering, field inventory, and cost. The remaining gap is routing guidance against sibling history/activity tools.

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?

With a single parameter and 100% schema description coverage, the schema fully documents video_id and its provenance from list_videos. The description contributes nothing parameter-specific, so this is the baseline 3.

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 (read) and resource (a video's history) and enumerates what the thread contains: rounds of changes, direct edits, caption fixes, authors, statuses, versions. It does not, however, distinguish itself from nearby siblings such as get_video_activity or list_versions, which an agent may plausibly confound.

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?

There is no when-to-use guidance: no statement of the situation that calls for the thread versus get_video_activity, check_video, or list_versions. The only usable cue is the free-cost note, which is a preference signal rather than a usage rule.

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