why

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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint. The description adds the requirement for canonical names but does not disclose behaviors like return format (though output schema exists) or handling of missing entities. Adequate disclosure for a safe, read-only tool.

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 extremely concise, with a useful example and clear instruction. Every word contributes to understanding, and there is no 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 tool has an output schema and annotations, but the description omits semantics for the optional max_hops parameter and lacks explicit guidance on when to use 'why' versus siblings. The example is helpful but the overall picture is incomplete for a three-parameter tool.

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 0%, and the description only clarifies from_entity and to_entity via the example. The max_hops parameter is completely unaddressed, leaving its purpose and effect undocumented. This is a notable gap given the low schema coverage.

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 returns a causal chain between two entities in the knowledge graph, with a concrete example. This distinguishes it from sibling tools like search or fetch by focusing on causal relationships.

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 instruction to use canonical names is explicit and aids correct invocation. The example demonstrates the intended argument order. However, it does not explicitly state when to use 'why' over siblings or mention any exclusions, but the context is clear enough.

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