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

With no annotations provided, the description must fully disclose behavior. It does explain the output payload and the evidence-based decision logic, but it fails to mention whether the tool has side effects (e.g., whether 'implementation lock' mutates any state) or requires prerequisites. This is a moderate transparency gap.

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 two sentences: the first front-loads the core function and return set, the second adds usage guidance. Every clause contributes meaningful information, and there is no redundant or filler text.

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?

Given the tool's complexity (8 parameters, no output schema), the description adequately covers purpose, return values, and usage context. It falls slightly short by not explaining how references are selected when reference_ids are omitted (the query parameter behavior) and leaving 'implementation lock' undocumented, but the overall picture is reasonably complete.

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 covers all 8 parameters with descriptions (100% coverage), so the description is not required to add parameter details. While 'business brief' and 'optional reference ids' align with schema, no additional semantic meaning is provided beyond the schema, meriting 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?

The description uses a specific verb ('Turn') with a clear resource ('business brief plus optional reference ids') and states the outcome ('reference-backed build direction'). It enumerates distinct deliverables (chosen direction, references, flow patterns, build plan, implementation lock, next calls), which clearly distinguishes it from siblings like build_from_reference or get_design_direction.

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 sentence 'Use when you want the agent to build from evidence instead of vibes' supplies a clear context for use. However, it does not explicitly name alternative tools or provide when-not-to-use conditions, so it stops short of a 5.

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