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

Annotations already declare this a read-only, idempotent, non-destructive, closed-world operation, so the safety profile is covered by structured data. The description nevertheless adds real behavioral context beyond them: the reason set is closed, unknown reasons surface as `other` with no guessed next step, and the call costs no credits. These are useful, but the return-format detail is partly the output schema's job, so this sits at a solid 3 rather than higher.

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 dense but front-loaded, leading with what it explains and following with the closed-reason/no-guess/no-credit caveats and the sibling routing. Every sentence carries distinct information, though the first sentence packs multiple clauses and the second paragraph is comparatively long.

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 diagnostic with an output schema, the definition covers purpose, behavioral quirks (closed reason set, `other` fallback), cost, and where adjacent operations live. Nothing an agent needs to call it correctly or interpret the result 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% for the single `ref` parameter, so the baseline is 3. The description adds only the scoping qualifier that the sync must be one of the user's own; it introduces no format or provenance detail beyond what the schema already supplies.

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 — explaining why one of the user's own syncs is not running — and pins the scope to recorded state and reason. It distinguishes itself from siblings by naming set_sync_paused and the Kalender Sync app for the adjacent operations. An agent can identify this as the diagnostic read for a single sync without opening any 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?

Explicitly routes the agent: resuming a paused sync is set_sync_paused, while reconnecting an account, reviewing the plan or replacing a calendar happens in the Kalender Sync app via next_step_url. Both the when-to-use and the when-not-to-use-this paths are stated rather than left to inference.

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