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

With no annotations, the description must convey behavior on its own. The verb 'Search' and 'QueryDescendants' imply a read-only query operation, which is useful, but the description does not explicitly state that it does not modify instances or describe what a result contains. This is adequate but leaves room for more transparency.

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 concise, front-loaded sentences with no filler. The first states the core function, and the second clarifies supported use cases. Every clause earns its place without 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?

The input schema fully documents parameters, limits, and output size limits, so invocation is well-covered. However, with no output schema, the description does not describe the return shape or provide guidance on interpreting results. It is minimally viable for a query tool, but not fully complete on its own. Note: the schema description mentions output size behavior, but return value semantics are unexplained, which is a moderate gap. The score reflects sufficient completeness for invocation, not full contextual richness.

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 schema already documents all four parameters clearly. The description adds a general summary of selector capabilities, but does not substantially enrich understanding beyond the schema's parameter descriptions, matching the baseline baseline of 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?

The description clearly states the tool searches Roblox instances using QueryDescendants selector syntax, naming the exact resource and query mechanism. It also lists the query categories (class, name, tag, property, attribute), which distinguishes it from broad tree traversal tools like get-descendants-tree or script-focused searches.

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 phrase 'Use for class, name, tag, property, and attribute queries' gives clear guidance on when this tool is appropriate. It does not explicitly mention alternatives or exclusions, so it stops short of a 5, but the intended usage is unambiguous.

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