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

The description adds a useful behavioral detail (fails cleanly on missing records) beyond the annotations. However, it does not mention whether the operation is idempotent, whether it overwrites existing links, or any other side effects, so transparency is partial.

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 very concise, consisting of two sentences with the core purpose stated first and a relevant failure behavior second. No superfluous content is present, and the structure is effective.

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?

For a simple four-parameter mutation with no output schema, the description adequately covers the main behavior. It mentions the failure case, but omits details about success return values or constraints on supported pairs (beyond examples), which could be useful but are not critical.

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 schema already provides descriptions for all four parameters (100% coverage), and the tool description does not add significant extra meaning beyond the schema text. The examples in the description (e.g., 'income+transaction') give some context but don't materially enhance parameter understanding.

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 action ('Link two entities') and provides examples of supported pairs, making the purpose understandable. However, it does not explicitly distinguish itself from the sibling tool 'unlink_entities', relying on the verb alone to convey the opposite action.

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?

It implies usage for creating links between entity pairs and notes the failure behavior, but does not explicitly state when to prefer this over alternatives (e.g., unlink_entities) or mention any preconditions beyond existence of the records.

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