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

Beyond the annotations, the description discloses data-handling behavior (task text and tool descriptions go to TypeSafe, Ontario does not persist task text, zero retention not promised), a prohibition on secrets/personal data, quota-exhaustion fallback to deterministic routing, and the hard boundary that it never executes tools or authorizes payment. That is exactly the extra context annotations cannot convey.

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?

Purpose is front-loaded in the first sentence and every subsequent sentence carries a distinct constraint (consent, privacy, non-execution, fallback). It is dense prose rather than a structured list, which slightly hurts scanability for a six-parameter tool.

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?

The return-or-abstain behavior and the no-execution boundary are stated, and an output schema exists to cover return shape. The gap is the multi-step payment context: the description never explains how free_preflight_complete, wallet_enabled, and max_usdc sequence with ontario_purchase_router.

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 all six parameters, including the network/payment constraints. The description echoes the allow_typesafe privacy warning but adds no new semantics for max_usdc, wallet_enabled, or free_preflight_complete, so the baseline of 3 applies.

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: 'task-to-tool matching', plus the optional Jev inference mode, so an agent knows this maps a task to a tool rather than executing anything. It does not, however, distinguish itself from plausible siblings such as find_x402_tool or ontario_purchase_router, so the agent must infer which matcher to pick.

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 conditions for the allow_typesafe branch ('With allow_typesafe=true...', 'Without consent, only Ontario's deterministic router is used'), which is useful. But it never says when to use this tool versus find_x402_tool, ontario_find-api, or ontario_purchase_router, leaving sibling selection to inference.

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