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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world behavior. The description adds useful context: it confirms the read-only scope and explains the SMS success semantics ('successful only after a delivery receipt'), which is not captured by annotations. It does not mention rate limits or pagination behavior, but those are minor given the annotation coverage.

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 tight sentences: the first front-loads purpose and scope, the second covers required/optional parameters and the SMS nuance. No sentence is wasted.

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 rich annotations, an output schema, and strong parameter descriptions, the description covers purpose, scope, date requirement, filtering, and SMS semantics. It omits pagination guidance and the 90-day range limit, but those are already covered in the schema, so the definition is sufficiently complete.

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 80%, so the schema already documents date formats, the 90-day cap, cursor rules, and limit bounds. The description only restates that a date range is required and repeats that the type filter is comma-separated, adding little beyond the schema.

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 states a specific verb and resource ('retrieve read-only transaction history') and scopes it to the authenticated SIMcloud account across named channels. It is clearly distinguishable from sibling tools like get_airtime_order or get_wallet_balance, which handle single orders or balances.

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 clear usage context: date range is required and an optional service filter can narrow results. It does not explicitly name alternatives (e.g., 'use get_airtime_order for a single order'), so guidance is strong but not complete.

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