set_item_length

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It explains item identification and length formats, but does not state whether setting the length mutates the item destructively, what happens if both length_time and length_measure are provided, or what error conditions exist (e.g., nonexistent track/item). This is a significant gap for a mutation tool.

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?

The description is well-structured and front-loaded with the main purpose, followed by compact bullet lists for item identification and arguments. It is appropriately sized for the tool's complexity, though a minor typo ('item(optional') and slight redundancy ('from start of item') could be cleaned up.

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?

Given the tool has 4 parameters with dual ID types and optional length specifications, the description covers the core usage patterns well. However, it omits edge cases such as behavior when neither length_time nor length_measure is supplied, or when both are supplied. The output schema exists, so return values are handled externally, but behavioral edge cases remain unaddressed.

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%, and the description fully compensates by clearly explaining track_index, item_id (including both valid types), length_time (seconds from start), and length_measure (measure:beat,fraction format). It also clarifies the optional relationship between length_time and length_measure, which is impossible to derive from the schema alone.

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 begins with 'Set the length of a media item,' a specific verb+resource combination that clearly defines the tool's function. It also distinguishes itself from sibling tools like set_item_position (which deals with position) by specifying 'length' as the target attribute.

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 provides clear context for when to use the tool: whenever you need to change a media item's length. It also explains how to specify length via two alternative parameters (length_time and length_measure) and how to identify items using either an integer index or a string ID. It does not explicitly mention alternatives or exclusions, but the scope is unambiguous.

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