Change the output quantities

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

Adds substantial context beyond the annotations: the file is backed up first, edits are logged, and changes can be undone via cm_revert_all. It also discloses the timing behavior (applies from next start) and the idle-simulation precondition, which the destructiveHint alone would not convey.

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?

Three information-dense sentences with the mutation action front-loaded, followed by safety/undo and preconditions. Nearly every clause earns its place, though the name-discovery sentence is slightly tangential to the core operation.

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 mutation tool, the description covers backup, logging, revert path, timing (next start), and the idle-simulation prerequisite. With an output schema present, return values need not be explained, so nothing essential is missing.

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 coverage is 100%, so the schema already documents add/remove/rate/preset in detail, including wildcards and the movie preset. The description contributes only the name-discovery source (cm_live) and does not elaborate on individual parameters, 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 pair (add/remove) and the exact resource modified (the project's output-quantities file), which cleanly distinguishes it from the read-only sibling cm_output_quantities. An agent can tell immediately what changes and where.

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 clear operating context: requires an idle simulation, applies from the next start, and tells the agent how to source names (via cm_live or another result file). It does not explicitly contrast with the sibling cm_output_quantities for reading the current list, leaving one alternative inference to the agent.

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