blast_radius

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

With no annotations, the description carries the full burden of behavioral disclosure. It explains the internal approach (combining reverse import graph with reverse call graph), the recall-first bias with a specific confidence threshold of >=0.3, and the rationale that missed impacted tests are worse than extra ones. It does not explicitly state that the operation is read-only or safe, but the impact-analysis framing implies it.

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 short and front-loaded: the purpose is in the first sentence, methodology and behavior in the second, and usage guidance in the final sentence. Every sentence adds distinct value with no repetition or filler.

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 output schema is present and the parameter schema fully describes the inputs, the description provides the necessary context: what the tool computes, how it prioritizes recall, what it highlights, and when to call it. An agent has enough to invoke it correctly and interpret its role relative to siblings.

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 the schema already documents target, depth, and limit with meaningful descriptions. The tool description adds no parameter-specific guidance beyond the schema, so the baseline score of 3 is appropriate.

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 opens with a clear purpose: 'Impact analysis: what a change here could break, and which tests to run.' It also differentiates itself from siblings by explaining it combines the reverse import graph with the reverse call graph and specifically highlights test files, which sets it apart from who_calls, what_it_calls, and related_symbols.

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 description gives explicit context for when to use the tool: 'Call this before editing shared code and after finishing, to pick tests.' It does not explicitly name alternatives or state when not to use it, but the workflow guidance is clear and actionable.

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