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

With no annotations, the description carries the full burden and does well: it discloses the auth requirement and the crucial side effect that current state is snapshotted as a new revision before the revert, telling the agent the operation is recoverable rather than destructive. It does not cover permissions granularity, error modes, or rate limits, so not 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?

Two tight sentences; the auth prerequisite is front-loaded and the behavioral caveat follows immediately. No filler sentences.

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 two-parameter mutation tool with no output schema, the description supplies the essential safety-relevant behavior (snapshot-before-revert) and the auth requirement. It leaves out what the revert returns and any failure behavior, but nothing critical to correct invocation is missing.

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 both parameters are already documented in the schema; baseline is 3. The description adds only the cross-reference that revision_id originates from vault-get-revisions, which is minor additional value.

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+resource (revert a vault session) and scopes it to an earlier revision, which cleanly separates it from siblings like vault-update-session, vault-clone-session, and vault-get-revisions. An agent can pick it without opening the schema.

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?

Gives the prerequisite ([Auth Required]) and routes the agent to vault-get-revisions as the source of revision_id, which is real usage guidance. It does not state when NOT to use it (e.g. vs. vault-update-session for non-revert edits), so it falls short of the 5 bar.

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