clips_set_length

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

Annotations already declare idempotent=true and destructive=false, but the description adds value beyond them: 'notes past the end stay but do not play' discloses the non-destructive side effect on out-of-range MIDI, and 'Undoable' confirms recoverability. It does not say what happens when the target slot is empty or whether an error is raised.

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?

One front-loaded clause plus a precisely chosen parenthetical and a one-word reversibility note. Nothing is padded and the most decision-relevant constraint (beats, retention behavior) comes first.

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 three-parameter mutation with full schema coverage, annotations, and no output schema, the description covers purpose, side effects, and reversibility. It stops short of stating failure modes or preconditions for slot occupancy.

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 baseline is 3, but the description adds real meaning for length_beats by explaining the consequence of shortening the loop (content is retained, not truncated). Track and slot semantics are left entirely to the schema.

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 ('Set'), a specific resource ('loop length of a session clip'), and a unit ('in beats'). The 'session clip' scoping cleanly separates it from siblings like arrangement_set_loop and clips_transform without needing to name them.

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 single-purpose nature makes the use case inferable, but there is no explicit guidance on when to use this versus alternatives such as clips_transform or clips_duplicate, and no stated preconditions (e.g. a clip must already exist in that slot).

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