vk_friends_get_mutual

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

The description identifies it as read-only ('Access level: read') and indicates it returns user IDs, but with no annotations, it could disclose more about constraints like required user existence or pagination behavior. It is adequate but minimal.

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 contains redundant information (VK API method, tool name, section) that doesn't add value. It could be more concise by combining the first and last sentences, but it is not overly verbose.

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 lack of annotations and output schema, the description does not cover return format, error conditions, or rate limits. For a tool with 7 parameters and no schema enhancements, more context is needed.

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 coverage is 100% with well-described parameters. The description adds no additional semantic value beyond what the schema provides, so a 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 clearly states it returns a list of user IDs of mutual friends of two users, which is specific and distinguishes it from sibling tools like vk_friends_get (returns all friends) and vk_friends_are_friends (checks friendship status).

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?

No guidance on when to use this tool versus alternatives. It only describes what it does without mentioning prerequisites, limitations, or scenarios where other tools would be more appropriate.

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