buildx_list

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

Adds behavioral context beyond annotations: raises RuntimeError on CLI failure, parses from JSON format, and drops a truncated final record. This complements the readOnlyHint/destructiveHint annotations with factual execution details.

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 short and front-loaded with the core action. It uses two sentences plus a returns bullet, with no redundant or filler content.

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 simplicity (0 params, list operation), the description covers all essential aspects: return type, error behavior, truncation handling, and relationship to sibling tools. Annotations provide safety profile, completing the picture.

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?

Tool has zero parameters, so there are no parameter semantics to clarify. The description does explain the return format and handling of truncation, but that's not parameter-related. Baseline 4 for 0 params is appropriate.

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?

Description opens with 'List builder instances,' a specific verb+resource statement. It also distinguishes from siblings by naming buildx_inspect for one builder's human-readable detail and buildx_use for switching the default.

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?

Explicitly states when to use this tool (machine-parsed view of every builder) and points to alternatives (buildx_inspect for detail, buildx_use to switch default), giving clear when-to-use and when-not-to-use guidance.

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