Unity API Communicator MCP Server

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

No annotations are provided, so the description carries full burden. It discloses that 'This may take a long time', which is a useful behavioral trait (long-running operation). However, it doesn't cover other aspects like whether it's destructive (likely yes, as it creates output), permissions needed, error handling, or what happens to existing builds.

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 three concise sentences with zero waste: first states the core action, second adds context about scenes, third warns about duration. It's front-loaded with the main purpose and 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 no annotations and no output schema, the description is moderately complete: it covers purpose and a key behavioral trait (long runtime). However, for a build tool that likely performs significant operations, it lacks details on output format, success/failure indicators, or side effects, leaving gaps in 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 description coverage is 100%, with the single parameter 'outputPath' well-documented in the schema. The description adds no additional parameter information beyond what the schema provides, so it meets the baseline of 3 for high schema coverage without compensating value.

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 action ('Start a build') and resource ('with the current build settings'), specifying it uses enabled scenes from Build Settings. It distinguishes from siblings like build_settings (which configures) or build_switch_platform (which changes platform), but doesn't explicitly contrast with all build-related tools.

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 when ready to execute a build with current settings, but doesn't specify when to use this versus alternatives like build_switch_platform or prerequisites (e.g., needing configured settings first). It mentions 'Uses enabled scenes from Build Settings', which provides some context but no explicit when-not or alternative guidance.

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