invariance_agent_set_key

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

Annotations already declare readOnlyHint=false and destructiveHint=false, and the description adds the meaningful behavioral fact that every node written after setting the key must be signed with the matching private key. It also links the key to server-side verification during invariance_run_verify, providing context beyond the annotations without contradiction.

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 sentences with the primary purpose front-loaded and the key consequence following. Every sentence earns its place without unnecessary detail.

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 one-parameter tool, the description covers purpose, effect, and the verification context. Combined with fully documented schema and annotations, nothing needed to correctly invoke the tool is missing.

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 has 100% coverage with a full description of the public_key parameter, including format and length. The tool description adds no additional parameter-specific details, only the contextual purpose of the key, so the 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 uses a specific verb ('Register or rotate') and a clear resource ('calling agent's Ed25519 public key'), which distinguishes it from sibling agent tools like invariance_agent_me and invariance_agent_create. It also adds the operational consequence of node-signing requirements, further clarifying its unique role.

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 provides clear context that the key must be set before writing signed nodes, and explicitly references the verification step in invariance_run_verify, implying when this tool is needed. It does not explicitly state when not to use or compare alternatives, so it falls short of a full 5.

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