add_anim_composite_segment

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

Beyond the annotations (readOnly=false, destructive=false, idempotent=false), the description discloses that the composite's length is recomputed after the append and details save-failure behavior: success becomes false with saved=false and save_error. That is meaningful side-effect and error-surface context the annotations do not carry.

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 front-loaded sentences cover the operation plus failure semantics, followed by a compact Returns enumeration. It is efficient, though the Returns list is slightly verbose given no output schema exists to carry it.

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?

With no output schema, the description usefully enumerates the return fields (composite_length, num_segments, segments, success, saved, save_error) and explains save failure. For a mutation tool with annotations already covering the safety profile, this is close to complete, missing only prerequisite/validation notes.

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 parameters like play_rate, start_pos, and loop_count are already documented by the schema. The description only indirectly touches on animation_path via 'referencing a real UAnimSequence' and adds no syntax or format detail beyond the schema, so the baseline 3 applies.

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 precise verb (Append) plus the exact resource being created (an FAnimSegment referencing a real UAnimSequence), the target container (UAnimComposite's AnimationTrack), and a follow-on effect (recompute length). This clearly distinguishes it from siblings like create_anim_composite or remove_anim_composite_segment.

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 the usage context (appending a segment to an existing composite), but never states when to choose this over siblings such as create_anim_composite or add_montage_segment, nor any prerequisites like the composite already existing. Usage is inferable but not spelled out.

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