compare_motions

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

It discloses non-obvious semantics — that the offset shifts B relative to A and that root_relative removes translation only — which annotations cannot convey. However, annotations declare readOnlyHint=false while destructiveHint=false, and the description never explains what side-effectful work happens (e.g., that synchronized views may be rendered or written), leaving the write-ish nature unexplained.

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?

Four short sentences, front-loaded with purpose then prerequisites then semantics then the interpretation caveat. No filler; every line adds information.

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?

An output schema exists, so return values need not be described, and the preconditions and offset semantics are covered. What is missing is the operational context implied by readOnlyHint=false: whether this job produces artifacts, how long it takes, and whether it consumes or writes job frames.

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%, so the description must carry parameter meaning, and it does explain the two genuinely ambiguous ones: offset_frames via 'B frame = A frame + offset' and the space enum via 'Root-relative removes translation only'. job_id/other_job_id and name/other_name remain undocumented but are self-evident by name.

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 first sentence gives a specific verb and resource ('Compare two completed motion samples') plus the distinguishing output ('synchronized exact-frame views and measured differences'). It does not explicitly contrast with nearby siblings like inspect_motion or analyze_motion_quality, so an agent must infer that this is the pairwise-diff tool.

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 sets preconditions ('Requires matching FPS and skeletons') and an explicit usage caveat ('inspect both candidates before choosing', differences do not rank realism). It stops short of naming when to reach for this versus inspect_motion or analyze_motion_quality, so the routing is implied rather than stated.

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