3D-MCP

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

No annotations are provided, so the description carries the full burden. It states 'update' which implies mutation, but doesn't disclose behavioral traits such as required permissions, whether updates are atomic or partial, error handling for invalid IDs, or impact on related data (e.g., animation curves). This leaves significant gaps for a mutation tool with complex nested parameters.

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 a single, efficient sentence with zero waste—it's front-loaded and directly states the core functionality. Every word earns its place, making it appropriately sized for the tool's complexity.

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 complexity (mutation tool with nested parameters, no annotations, no output schema), the description is incomplete. It lacks behavioral context (e.g., side effects, error modes), usage guidelines, and output expectations. For a tool that modifies multiple keyframes with detailed input schema, more context is needed to guide effective agent use.

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?

The schema description coverage is 100%, with detailed descriptions for all nested parameters (e.g., 'time', 'value', 'tangentIn'). The description adds no additional meaning beyond the schema—it doesn't explain parameter interactions, constraints, or usage examples. With high schema coverage, the baseline is 3, as the description doesn't compensate but doesn't detract either.

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 'Update multiple Keyframes in a single operation' clearly states the verb ('Update') and resource ('Keyframes'), but it's vague about what 'update' entails—it doesn't specify which attributes can be modified (e.g., time, value, tangents). It distinguishes from 'createKeyframes' and 'deleteKeyframes' by implying modification of existing items, but doesn't differentiate from other update tools like 'updateChannels' or 'updateJoints' in terms of scope or behavior.

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?

No guidance is provided on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., needing existing keyframes), compare to single-update methods, or specify scenarios like batch efficiency. The context is implied as bulk operations, but no explicit when/when-not rules or sibling tool references are included.

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