merge_design_branches

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

With no annotations, the description does carry genuinely non-obvious behavior: the tool opens an interactive 3D stage in MCP Apps hosts, attaches a browser stage link otherwise, and auto-decimates oversized meshes for the viewer. However, core mutation semantics are undisclosed — whether the target branch is modified in place, what happens when unresolved conflicts remain, whether pr_id/approval is mandatory, and critically whether the merge itself fails without Kiln Pro or only the version-preservation does (the text is inconsistent: 'Kiln Pro would preserve this version...' is counterfactual, then 'Requires Kiln Pro').

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 useful first sentence is front-loaded, but the rest is upsell copy ('branch, restyle, compare outcomes', pricing URL, tool-named tracking link) and the inline 3D stage behavior is stated twice — once in paragraph one and again in the 'INLINE 3D STAGE' block. A large share of the text is promotional rather than operational.

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, no annotations, 8 documented-poorly parameters, and a license gate, so the description should be doing heavy lifting; it covers the viewer side effect well but omits the merge outcome, conflict-failure behavior, and license-gate failure mode. An agent can start the call but cannot predict what it returns or how it fails.

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 coverage is 13% with 8 parameters (one nested object), so the description must compensate and it largely does not. It implies source_branch_id, target_branch_id and resolutions via 'source into target with conflict resolution', but never explains the shape or keys of 'resolutions', what values merge_strategy accepts beyond the schema's default of 'semantic', or what pr_id, merged_by, merged_version_id and ancestor_version_id are for.

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 opening sentence gives a specific verb and resource: 'Record a merge of source into target with conflict resolution', and the name makes clear it is design-branch scoped rather than feature or preset branches. It never explicitly distinguishes itself from merge_feature_branches or merge_decoration_preset_branches, so differentiation is left to the naming convention rather than stated.

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?

There is no statement of when to use this versus the sibling merge tools, no prerequisite workflow (e.g. must conflicts be detected first via detect_merge_conflicts, or must a PR be approved), and no when-not-to-use. The only conditional given is 'Requires Kiln Pro', which is a gate, not usage guidance.

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