brain_link

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

No annotations are provided, so the description carries the full behavioral burden. It discloses that linking is bidirectional, which is useful, but says nothing about permissions, whether existing links are overwritten, what happens if either note does not exist, or how the `rel` relationship behaves.

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 two short sentences with no waste, and the core action is front-loaded. Even the second sentence is brief enough not to undermine clarity.

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 mutation tool with no annotations and 0% schema description coverage, this is not complete enough. The output schema means return values need not be explained, but the description still omits key details about `rel`, link conflicts, and error behavior that an agent needs before invoking the 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%, so the description should explain the parameters. It implies that `a` and `b` are the two notes, but it never mentions `rel`, its default value, or what relationship values are meaningful. The description adds little beyond a vague mapping to two of the three parameters.

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: "Link two notes both ways." That is clear and actionable. It does not explicitly differentiate from siblings such as brain_encode or brain_supersede, but its purpose is still distinct.

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 only guidance is a value heuristic: "Links across cortices are the most valuable." There is no explanation of when to use this tool versus a plain note update, when not to use it, or what prerequisites or failure conditions exist.

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