Enable or disable a URL user rule

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

Annotations already declare destructiveHint=true, readOnlyHint=false, openWorldHint=false, and the description is consistent with them. It adds real context beyond the annotations: the write is optimistic-concurrency bound ('using its current revision') and disabling has a stated downstream consequence (unavailable even to exact flow selections). It stops short of saying what happens on a revision mismatch or whether re-enabling restores state.

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?

Very short and front-loaded with the action, with no filler sentences. The follow-up fragment 'No fetch.' is terse to the point of ambiguity — it is unclear whether this is a cost/latency note or an instruction to omit a fetch step.

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?

An output schema exists, so return values need not be explained. However, for a three-parameter mutation with zero schema documentation and a destructive hint, the description leaves the identifier format, the consequence of a stale revision, and revision-mismatch error behaviour unstated — adequate but with clear gaps.

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 0%, so the description carries the full burden. It partially compensates by implying the concurrency-token role of 'expected_revision' via 'using its current revision', but the 'rule_id' format is only obliquely described as 'user:<name>' (and contradicts the param name), and the boolean 'enabled' is not disambiguated at all.

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 ('enable or disable') and resource ('user:<name> subscription', i.e. a URL user rule), so the agent knows exactly what state change occurs. It is distinguishable from the sibling set (list/get/subscribe/refresh/rollback/delete_user_rule), though it never names those siblings explicitly. Minor wobble: the description says 'user:<name>' while the schema key is 'rule_id'.

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?

No when-to-use guidance and no routing to alternatives such as delete_user_rule, rollback_user_rule, or subscribe_user_rule. The only hints are operational ('No fetch') and consequential ('Disabled user rules are unavailable even to exact flow selections'), which inform impact but not tool selection.

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