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

With no annotations, the description carries the burden and does disclose key traits: the call requires authentication, it mutates only the enabled state of an existing watch, and disabling affects only future runs. It stops short of stating whether an in-flight run is cancelled, whether the change is reversible, or what the call returns.

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 compact sentences, front-loaded with the core state-change purpose and the enable/disable semantics, followed by the routing to sibling tools. No filler, and the negative scope ('does not create... or edit its query') earns its place.

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 two-parameter mutation with no output schema and no annotations, the description covers auth, mutation scope, and sibling routing adequately. It omits only the return shape/idempotency details, which are minor for a simple boolean toggle.

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 both parameters are already documented; the description largely restates the enabled semantics (future scheduled executions on/off) and adds the note that cadence and spending limits are preserved. This adds marginal meaning beyond the schema, consistent with the baseline 3 for full coverage.

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 ('Authenticated state change for an existing recurring paid watch') and explicitly scopes what it is not: it does not create a watch or edit its query. This lets an agent separate it from create_recurring_paid_watch and the read-only list tool 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?

Gives explicit when-to-use branches (enabled=true for future scheduled runs under saved cadence/limits, enabled=false to stop future runs) and names the alternatives for the adjacent operations: create_recurring_paid_watch to create one and list_recurring_paid_watches to obtain an existing watch_id. Nothing is left to inference.

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