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

Annotations only declare readOnlyHint=false and destructiveHint=false. The description goes well beyond that: it discloses reversibility, the two distinct refusal modes (unfinished steps, live-flow plan limit), the rationale for the silent-failure rule, and the important fact that a refusal leaves state unchanged so the user can retry. Only auth/permission behavior is unstated.

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-loaded with the action and its effect, then the reversal path, then the failure modes. Every sentence adds operational value, though phrasing like 'a sentence worth repeating' is slightly editorial and could be tightened.

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 single-parameter mutation with annotations covering the safety profile and no output schema, the description is nearly complete: action, effect, reversal, and failure conditions are all covered. The missing piece is permission/auth requirements.

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% and there is a single required 'flowId' parameter, so the schema already carries the parameter semantics. The description adds nothing about the id format or where to obtain it, making the baseline 3 appropriate.

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+resource ('Switches a DM flow on') plus the concrete effect (it will answer matching direct messages). It explicitly names flows_pause as the counterpart, so an agent can separate this from the other flows_* siblings without opening a 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?

Names the alternative for the reverse operation ('Reversible with flows_pause') and lays out the two conditions under which the call is rejected. It gives clear context for when the tool applies, though it doesn't spell out prerequisites like required scopes or trigger configuration.

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