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

Annotations already establish readOnlyHint=true and openWorldHint=false. The description adds valuable behavioral context: the key algorithms, that the keys are public and intended for offline signature verification, and that the endpoint is free. It does not cover auth requirements or rate limits, but with annotations present this is a solid contribution.

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?

Three short sentences, front-loaded with the resource and algorithm details, then the action, then pricing. No filler.

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 zero-parameter, read-only key retrieval tool with an output schema and readOnlyHint/openWorldHint annotations, the description supplies everything an agent needs: what the keys are, their algorithms, the intended use, and cost. No critical gaps.

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 tool takes zero parameters, so the 4 baseline applies. The schema has no properties and the description adds no parameter details because none exist.

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 identifies the resource as Privi's public signing keys and names the exact algorithms (Ed25519, ML-DSA-87), so an agent knows what the tool provides. It does not use an explicit retrieval verb or mention sibling tools like fortress_tpi_*, so it is clear but not fully differentiated from the broader fortress family.

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?

It gives a concrete use case—'Pin these to verify Privi signatures offline'—which tells the agent when to call it. It does not name alternatives or exclusions, so it falls short of the 5-level routing guidance.

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