Last recorded source-drift snapshot

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

Annotations already declare readOnlyHint and idempotentHint, so the safety profile is clear. The description adds meaningful behavioral context beyond that: the result is stale by design, it reflects the last 'rrt drift generate', and reading the file directly is equivalent. This is exactly the kind of caveat an agent needs.

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?

Three short sentences, each earning its place: the result and source, the staleness caveat with the comparison command, and the direct-file alternative. The key scoping information 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 zero-parameter, read-only tool with an output schema, the description is complete. It covers what the tool returns, the source file, the staleness semantics, and how to get the same data more directly. Nothing an agent needs to invoke it correctly 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?

The tool has zero parameters and the schema coverage is 100%, so there are no parameter semantics to document. Per baseline rules for 0-param tools, this is appropriately handled; the description focuses on output meaning rather than input details.

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 ('Return'), the resource ('.rrt/drift.lock.toml'), and the content ('file hashes and symbols'). It distinguishes itself from a current-state check by explicitly saying it reflects the last snapshot, and it names the sibling 'rrt drift check' as the alternative.

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 says when to use it (to inspect the recorded snapshot) and when not to (when current state is needed, run 'rrt drift check'). It also provides an alternative via direct file read, which gives an agent clear routing guidance.

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