Set mixer routing (src -> dst)

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

Annotations provide idempotentHint=true, but the description adds 'calls afterRoutingChanged' (side effect) and 'Snapshot + readback; undo with fl_rollback_last_change', giving deeper insight into behavior. No contradiction with annotations.

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 sentences: first states purpose and side effect, second covers undo mechanism. Extremely concise with no wasted words. Front-loaded with key information.

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 simple routing toggle, the description covers purpose, side effect, and undo. Output schema exists, so return values are unnecessary. It doesn't mention prerequisites (e.g., track existence), but that is implied by the schema. Minor gaps but overall sufficient.

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 each parameter is already well-documented. The description adds no additional parameter-level meaning beyond echoing 'src -> dst'. Baseline 3 is 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?

The description clearly states it 'Enable/disable a send from src -> dst', specifying the verb and resource. It distinguishes from siblings by focusing on routing, not volume or pan. The mention of 'calls afterRoutingChanged' adds behavioral context.

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?

The description implies usage for setting mixer routing and mentions undo with fl_rollback_last_change, suggesting a workflow. However, it does not explicitly state when not to use it or compare to alternatives like fl_get_routing or fl_set_mixer_*.

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