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

Annotations already cover safety (readOnly, idempotent, non-destructive), yet the description adds the crucial operational caveat that observed history begins at ingest time and most sections therefore return diff: null. That failure mode and its workaround are exactly the kind of behavioral disclosure annotations cannot carry.

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 blocks: what it does, how each mode is used, and what it cannot do plus the escape hatches. Every sentence earns its place and the caveats are front-loaded rather than buried.

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 an output schema present, return-value shape need not be described, yet the description still flags the diff: null case. Tool is read-only, no auth or rate-limit concerns to state, and the alternatives for out-of-range history are given, so an agent has everything needed to call it correctly.

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 only 20% (only citation is documented), so the description must compensate and it does: it defines the semantics of both mode values and notes that observed mode can optionally be bounded between two dates, which is the only explanation of from_date/to_date anywhere. format remains unexplained, but the two decisive parameters are covered.

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 (word-level diff) plus the exact resource (a North Carolina statute section between two versions), and immediately distinguishes its two operating modes. An agent can tell this apart from get_statute, amendment_history, and pending_changes without opening any schema.

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?

Explicitly routes mode="pending" to the 'what will change on 1 October' question and mode="observed" to already-recorded versions, and names two alternative tools (amendment_history for earlier change dates, pending_changes for pending text) with the condition that selects each.

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