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

Beyond the readOnlyHint annotation, the description discloses important behavioral traits: only deliberate relationships count, bulk-imported and system-inferred edges are excluded, and an empty list is returned when no mutual connections exist. It also instructs the agent to report that absence honestly, which is valuable runtime guidance.

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 compact and well-structured: definition first, then examples, then two key caveats. Every sentence carries useful information, and there is no redundant repetition of the title or schema.

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 low complexity, two well-documented parameters, and readOnlyHint annotation, the description is nearly complete. It clarifies the return behavior (empty list) and the relationship filter. It does not describe the exact output structure for non-empty results, but the absence of an output schema is partially mitigated by the clear statement that graph objects are returned.

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 already covers both parameters with 100% description coverage ('exact object_id'). The tool description adds context that these are 'two given objects' and gives examples of people/companies, but it does not need to add more since the schema is already explicit. Baseline 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 states a specific verb and resource: finding objects in the user's graph directly connected to BOTH of two given objects. It gives concrete examples (mutual contacts between people, shared people between companies), which clearly distinguishes this from generic connection or search tools like search_connections or find_paths.

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 clearly implies when to use this tool: when you need mutual or shared connections between two entities. It does not explicitly name alternatives or exclusions, but the BOTH condition and examples provide enough contextual guidance for an agent to select it appropriately.

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