counterexample

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

With no annotations provided, the description carries the full behavioral burden. It clearly discloses that the search is bounded and truncated, and that this makes a negative result non-conclusive. This is a significant and honest behavioral caution. It does not spell out output format or what happens on no result, but the core semantics are disclosed.

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 sentences with no filler. The first sentence defines what the tool does with the concrete resource and constraints, and the second is a valuable caveat that clarifies the meaning path absence. Each sentence earns its place.

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 six parameters, no annotations, no output schema, and low parameter documentation, the description is a bit thin. It covers the core operation and the truncation caveat, but does not describe the return value shape, the exact roles of `depth`/`limit`, or error behavior. However, the default values and schema names provide enough baseline to call the tool if the agent makes reasonable assumptions.

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 only 17%, so the description must compensate. It clarifies src, sink, and validator as source, destination, and the guard being avoided. Depth and limit are only indirectly covered by the words "bounded" and "truncated," and their specific semantics are left to the schema defaults.

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 a specific operation: find a bounded call path from src to sink that avoids a named validator/guard. It also positions this as "the inverse reachability move," which distinguishes it from reachability-oriented sibling tools and signals that it creates counterexample paths rather than ordinary reachability results.

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 implies when to use this tool through "inverse reachability move," but it does not explicitly name alternatives or state what should be used instead in other scenarios. The caution that absence of a path is not proof when the search is truncated is helpful, but the when-to-use guidance is mostly implicit.

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