signalgrid_time_machine

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

Beyond the annotations (read-only, idempotent, non-destructive), the description discloses edge cases: auto_backup can be null if unreadable, and latest_backup may be a snapshot path or error text. It also explains the meaning of a stale backup, adding behavioral context that helps the agent interpret results. No contradictions with annotations.

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?

The description is concise and well-structured: a one-sentence purpose, a brief motivational context, and a clear list of return keys. Every sentence earns its place without redundancy or fluff.

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 simple zero-parameter read-only tool, the description is complete. It explains the return keys, the meaning of null/error values, and the practical significance of the data. The existence of an output schema supplements the return structure, and the description covers the rest.

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, so schema coverage is trivially 100%. The baseline for zero parameters is 4. The description does not need to explain parameters but instead explains the output structure, which is useful.

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?

The description clearly states the tool's purpose: reporting Time Machine posture including backup on/off state, destinations, and latest backup. It uses specific terminology and distinguishes itself from sibling tools by focusing on Time Machine specifically. The return structure is outlined, leaving no ambiguity about what the tool does.

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?

The description provides context for when this tool is useful: identifying data-loss risk and drift signals from stale backups. It does not explicitly name alternative tools or exclusion criteria, but the specific domain and the drift signal context make usage scenarios clear. For a zero-parameter read-only tool, this level of guidance is adequate.

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