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

No annotations are provided, so the description must carry the full transparency burden. It discloses the npub requirement and credit billing, which is useful, but it omits other behavioral traits such as whether duplicate links are prevented, what happens on failed billing, or how the graph structure is affected. The minimal disclosure leaves significant gaps.

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 a single, front-loaded sentence with zero filler. It delivers the core action and the key prerequisite without extraneous text, making it efficient and easy to scan.

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?

Despite having an output schema and 11 parameters, the description is very brief. It fails to mention important context such as the meaning of relation types (beyond schema), the consequences of creating a link, or any special handling of optional fields. The tool likely needs more operational context for an agent to invoke it safely and effectively.

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 91%, so the schema already documents all parameters well. The description reinforces thought_id_a/thought_id_b and npub but adds no new semantic meaning beyond the structured field descriptions. Baseline of 3 is appropriate when the schema does the heavy lifting.

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 'Create a relationship between two thoughts by ID' with a specific verb ('Create'), a clear resource (relationship between thoughts), and required identifiers. This distinguishes it from sibling tools like brain_update_link and brain_delete_link.

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 verb 'Create' implies this is for new relationships, and the requirement for npub indicates a prerequisite. However, it gives no explicit guidance on when to prefer this over alternatives (e.g., brain_update_link) or when not to use it, leaving usage context implied rather than stated.

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