native_build

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

Annotations provide openWorldHint=true and idempotentHint=false. The description adds valuable behavioral context: output streams to timeline, failure behavior returns a checklist for missing Android dependencies. No contradiction with annotations.

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 highly concise: two sentences. First sentence front-loads the purpose and key behavior. Second sentence covers prerequisites, failure case, and next steps. No wasted words.

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?

The description covers prerequisites, failure behavior, and follow-up tool (native_open). However, it does not describe the return format on success (e.g., what 'started:true' looks like) or detailed output structure. Given no output schema, this is a minor gap.

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?

Both parameters are fully described in schema (100% coverage). The description adds extra meaning by mapping platform to specific Expo commands and mentioning that cwd defaults to active pane. This enhances understanding beyond the schema.

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: 'Build + launch the native dev build for the active pane' with specific commands (expo run:ios/android). It distinguishes from siblings by mentioning native_open as a follow-up step, implying this tool is for building and launching while native_open is for driving after boot.

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 provides clear usage context: 'Cockpit-only, local build' and lists required toolchains for each platform. It also explains behavior when Android toolchain is missing (returns started:false with checklist). However, it does not explicitly state when not to use this tool or mention alternatives beyond native_open.

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