previewCodeAction

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

The description confirms the read-only nature by stating 'without applying,' which aligns with the annotation 'readOnlyHint: true.' However, it adds no extra behavioral details beyond what the annotation already provides (e.g., no mention of what happens if the action is invalid or rate limits).

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 extremely concise with two sentences. The first sentence immediately states the core purpose, and the second provides usage guidance. No unnecessary words or redundancy.

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?

For a simple preview tool with no output schema, the description covers the essential purpose and usage. It could be more complete by briefly describing what the preview output looks like (e.g., a diff or list of changes), but it is sufficient for an agent to understand how to use it.

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 input schema has 100% description coverage for all 6 parameters, so the schema already explains each parameter in detail. The tool description does not add any additional meaning or context about the parameters, so it provides no extra value 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 'Preview edits a code action would make without applying' clearly states the tool's purpose. It specifies the verb 'preview' and the resource 'edits a code action would make,' and distinguishes it from the sibling 'applyCodeAction' by advising to use before applying.

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 explicitly says 'Use before applyCodeAction,' providing clear context for when to use this tool. It names the sibling tool as the subsequent step, but does not mention when not to use it or alternatives like 'getCodeActions' to list available actions.

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