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

With no annotations, the description carries the full behavioral burden. It does disclose the auth requirement ('[Auth Required]') and that the operation is a read ('List'), which is real added context. It says nothing about ordering, pagination, or how many revisions are returned, so the disclosure is partial.

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 with no filler, and the most decision-relevant fact (auth required) is front-loaded before the purpose. Every clause earns its place.

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 tool with no output schema, an agent needs to know what a 'revision history' entry contains, but the description does not characterize the return at all. Auth is covered and the purpose is clear, so it is adequate, but the return shape remains undefined.

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?

There is a single parameter ('id') with 100% schema description coverage, so the schema already documents it. The description adds no extra meaning such as whether the id refers to the session's current or historical identifier. Baseline 3 applies when the schema does the heavy lifting.

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: 'List the revision history of a vault session.' That is clearly distinct from vault-get-session and vault-list-sessions, and it names a related sibling (vault-revert-session). It stops short of explicitly contrasting itself with those siblings, so it is clear but not fully self-differentiating.

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?

'Use with vault-revert-session' implies the intended workflow (inspect revisions, then revert), which is useful implied guidance. However, it never states when to prefer this over vault-get-session or what conditions make a revert appropriate, so usage is only suggested, not specified.

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