marker_add_region

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

With no annotations, the description carries the full burden. It discloses key behavioral traits: errors on duplicate names, parameter constraints (position >=0, length >0), and default loop_mode. It also mentions the parameter types and default behavior, which is valuable. However, it doesn't disclose any side effects (e.g., does it modify existing regions?) or return behavior, but it's fairly transparent for a simple add operation.

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 concise: a brief purpose sentence followed by a clear arg list. It's front-loaded with the primary action. However, the arg list could be tighter; some items like 'loop_mode' lack explanation of each option, and the description could be more structured (e.g., grouping destination region context). But it's not bloated.

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 complexity (5 params including enums-like loop_mode) and no output schema, the description is sufficient for basic usage but omits important details: it doesn't specify the meaning of 'loop_mode' options (Looping vs Magnet), doesn't describe return values, and doesn't explicitly state that the track must exist or that the name is unique. The description covers the core but lacks edge-case context.

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 0% per context signals, meaning the description is the only source of parameter meaning. The description provides a terse list of args with minimal context: e.g., 'track_target: Marker track {guid} from event_add_marker_track.' This adds some meaning beyond schema titles, but it doesn't explain formats (e.g., name restrictions, position precision) or how loop_mode affects behavior. With 5 params and no schema descriptions, the description should be more detailed to compensate.

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 the tool's purpose: adding a labeled range (region) to a marker track, with usage examples like section transitions. It distinguishes from siblings by mentioning 'destination (loop) region' and errors on duplicate names, making it specific. However, it doesn't explicitly compare to sibling tools like marker_add_named or marker_add_transition_region, so it's not fully differentiated.

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 context (adding destination regions) but does not explicitly state when to use this tool versus alternatives like marker_add_named or marker_add_transition_region. It also doesn't provide exclusion criteria or mention required parent tracks beyond the track_target parameter. The mention of 'loop_mode' implies use cases but not explicit guidance.

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