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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered. The description adds real behavioral context beyond them: every prompt edit is snapshotted into an append-only table, implying complete and immutable history, which is useful for judging result reliability.

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 first establishes what is listed, the second establishes why and what to do next. No filler, and the purpose is front-loaded.

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 read-only history listing with no output schema, the description is sufficient: it tells the agent what the records are, why the list is complete, and how the results are meant to be consumed (via agents.prompt_restore). Annotations cover the safety profile, and pagination parameters are fully described in the schema.

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 all four parameters (agent_id, limit, before_version cursor, in_workspace) are already documented in the schema. The description adds no extra syntax or semantics for them, so the baseline 3 applies.

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 past versions of an agent's prompt_text') and adds the domain detail that these are append-only snapshots of every edit. It also distinguishes itself from the related restore path by naming `agents.prompt_restore` as the destination for a chosen version.

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?

Explicitly frames the use case: browse history to find a prior known-good version and then copy it into `agents.prompt_restore`, which effectively routes the agent between the two tools. It stops short of stating when *not* to use it (e.g., to fetch current prompt text, use agents_get), so it is clear but not exhaustive.

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