uvcs_merge_preview

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds real behavioral context by stating 'without changing anything' and explaining that providing a destination changes where the preview is computed (on the server for that branch). It does not discuss permissions, rate limits, or output pagination, but with annotations covering safety this is a meaningful addition.

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 tight sentences with zero filler: it front-loads the read-only preview purpose, then details the destination behavior. Every sentence earns its place.

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?

There is no output schema, so the description usefully enumerates the categories of preview results. Annotations cover the safety profile and the schema covers all parameters completely. The only minor gap is the lack of explicit guidance on how this tool relates to merge_prepare and merge_confirm.

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%, so the baseline is 3. The description adds value beyond the schema for the 'destination' parameter by explaining that its presence shifts preview computation to the server for that branch, which is not explicit in the schema's own description.

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 uses a specific verb and resource ('Preview a merge') and immediately enumerates the three categories of output (files taken from source, added/moved/deleted items, conflicts). This distinguishes it from the merge_prepare and merge_confirm siblings without needing to name them.

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?

It clarifies the effect of supplying or omitting 'destination' (workspace branch vs server-side computation), which is useful usage context. However, it never explicitly says when to use this preview versus uvcs_merge_prepare or uvcs_merge_confirm, leaving the alternative-routing guidance implied rather than stated.

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