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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), so the bar is lower. The description adds a genuine behavioral nuance in 'as the ledger serves it' — i.e. values are server-authoritative rather than locally recomputed — and points at the recomputation companion tool. It does not mention auth or failure behavior, but for a read tool under full annotation coverage this is solid.

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 front-loaded sentences with no filler; the purpose leads and the companion hint trails. The enumerated return fields are slightly redundant given a full output schema, which is the only minor bloat.

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 one-parameter read tool with a complete output schema and full annotation coverage, the description supplies enough: identity, source of truth, and a follow-up tool. Error handling and pagination are unaddressed but largely inapplicable here.

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?

Single parameter with 100% schema coverage and a schema description ('entry number'), so the schema already carries the semantics. The description's 'ledger entry n' only restates the parameter without adding format, range, or lookup behavior beyond the schema's minimum:1 constraint.

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 ledger entry n') and describes the shape of what comes back, which distinguishes it from the sibling nenrin_ledger_head (head vs. arbitrary entry). It does not explicitly frame the contrast with that sibling, keeping it just short of a 5.

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?

Offers one usage cue — 'Pair with jidec_how_to_verify to recompute it' — which implies the verification workflow. It never states when to use this over alternatives like nenrin_ledger_head or jidec_replay, so the when-to-use guidance is implied rather than explicit.

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