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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds the state model (pending vs anchored, returning ledger entry and batch), but with an output schema present this largely restates what the schema conveys, so it adds only modest behavioral value.

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?

Two sentences, both earning their place: the retrieval semantics come first, the motivating use case second. No filler, though the second sentence could be tighter.

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?

With one documented parameter, rich annotations, and an output schema, the description only needs to cover purpose and a reason to call it — both are present. Nothing essential is missing for correct invocation.

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 100% and the single field is documented as '64-hex record SHA-256'; the description mirrors that wording without adding format, validation, or error-handling detail. Baseline 3 applies since the schema already does the work.

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?

States a specific verb and resource ('Return one NENRIN witness record') plus the exact lookup key (record SHA-256), which cleanly distinguishes it from sibling ledger tools like nenrin_ledger_entry or nenrin_ledger_head.

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?

Gives an explicit use case — 'check a walk someone says they submitted' — which tells the agent when this tool is relevant. It stops short of naming alternatives or exclusions (e.g., how to list multiple records), so it is clear context without full routing guidance.

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