Plumb · describe

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint. The description adds meaningful behavioral context: output is text-only per-region narrative and flat child summary derived from PDS. No contradictions 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?

Two sentences delivering purpose, use cases, output format, and sibling guidance with no superfluous content. Front-loaded and efficient.

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 5 parameters and no output schema, description explains return narrative and summary, mentions derivation from PDS, and links to siblings. Lacks parameter-specific behavior details but sufficient for most agents.

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 covers all 5 parameters with descriptions (100% coverage). The description does not add extra meaning beyond schema; it only summarizes output format. Baseline 3 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?

The description clearly states it provides a 'text-only visual description of a Figma screen or node', specifies use cases (image-blind harness, sandboxed Read, token-conscious flows), and distinguishes from siblings by suggesting pairing with plumb_node and plumb_screenshot for complementary info.

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 says when to use (when screenshot cannot be read) and when to pair with other tools (plumb_node for structural spec, plumb_screenshot for pixel reference), providing clear context versus alternatives.

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