update_look_partial

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

No annotations are provided, so the description carries the full behavioral burden. 'Safely' is undefined marketing language with no explanation of what makes it safe, whether it is a mutation, what permissions are needed, or what happens to existing fixture values when mergeFixtures is false. The merge/replace semantics live only in the schema, not the description.

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?

A single front-loaded sentence naming the primary action and the optional extension; there is no filler. It is arguably too terse for a mutation tool, but as raw concision it is 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?

For a no-annotation mutation tool with no output schema and five parameters, the description is too thin. It omits return behavior, the effect of mergeFixtures=false (destructive replace), and how it relates to the near-identical 'update_look' sibling, leaving real gaps an agent must resolve elsewhere.

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% and every parameter (lookId, name, description, fixtureValues, mergeFixtures) is documented inline, so the schema does the heavy lifting. The description adds nothing about parameter formats or defaults beyond what the schema already states, warranting the baseline 3.

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?

States a specific verb and resource ('update look metadata') plus the optional fixture-value merge, so the operation is understandable. However, it never differentiates itself from the sibling 'update_look' or 'bulk_update_looks_partial', leaving the 'partial' distinction to be inferred from the name alone.

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 guidance on when to choose this over 'update_look', 'bulk_update_looks', or 'bulk_update_looks_partial'. The word 'optionally' describes the fixture values but gives no condition under which merging versus metadata-only editing is appropriate.

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