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

Without annotations, the description carries the full behavioral burden. It discloses the cost (0.002 USDC) and that it detects replays/conflicts, but says nothing about side effects, authentication needs, rate limits, or what happens on detection. This is insufficient for a guard-type tool.

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?

A single, front-loaded sentence with no wasted words. The price is tacked on after a semicolon, which is slightly awkward but still efficient and informative.

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?

An output schema exists, so return values need not be explained. However, with no annotations, the description should cover prerequisites, behavior, and usage context — it provides none of these, leaving significant gaps for an agent to call the tool 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 100%, so the schema already documents the two required parameters. The description adds no param-specific meaning (e.g., format of idempotency_key or allowed values for action), so baseline 3 is appropriate.

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 names a specific verb ('Detect') and resource ('safe replays and conflicting idempotency-key reuse'), making the tool's function clear. It does not explicitly differentiate itself from siblings like duplicate_charge_detector or concurrency_guard, but the idempotency-key focus is distinctive enough.

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?

No guidance is given on when to use this tool versus alternatives, prerequisites, or exclusions. The description only states what it does and the cost; an agent must infer usage entirely.

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