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

Adds real context beyond annotations: idempotent set-semantics with the changed:false signal, both directions of a two-way sync affected together, no deletion on pause, and copies removed again on resume – which usefully explains the destructiveHint. It also discloses zero credit cost. Not a 5 only because it does not say what permissions or error responses to expect.

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?

Front-loads the core action and the non-toggle semantics, then layers conditions. The later sentences are dense and somewhat long, but each carries a distinct constraint (side effects, eligibility, cost) rather than restating the name.

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 state-mutating tool this covers semantics, side effects, eligibility limits, ref provenance and cost, and an output schema exists to explain the return. An agent has everything needed to invoke it correctly.

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 ref and paused are already documented (ref from a current list_syncs result, true = paused). The description reinforces the ref-provenance rule but adds no format or constraint detail beyond the schema, 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 concrete verb and resource: "Sets whether one of the user's own syncs is paused." It immediately disambiguates from a toggle and scopes the operation to the caller's own syncs, so an agent can distinguish it from siblings like create_sync, delete_sync and diagnose_sync.

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?

Gives explicit preconditions and exclusions: only syncs into sync_target calendars can be paused, and syncs paused due to plan/calendar/update issues cannot be resumed here. It also names the source of the ref ("a current list_syncs result"), routing the agent to the right upstream tool.

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