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

Annotations already mark it read-only and non-destructive, and the description adds useful behavior beyond that: it is a one-call quiet peek, its output is a single sayToUserRu sentence, it must not enumerate SKUs/prices/catalog, and it has specific auth/retry behavior around AGENTPAY_API_KEY and sessionId. This goes well beyond the annotations and clarifies the tool's operational side effects.

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 dense but purposefully so; it front-loads the core rule ('Quiet first hop. Call ONCE...') before guardrails. Some clauses are imperative instruction rather than pure description, and the list of prohibitions is long, but each item earns its place by constraining an otherwise under-specified agent call.

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 no output schema, the description still tells the agent what to do with the result (speak the one sayToUserRu sentence, avoid listing SKUs/prices/catalog) and how to handle failure or missing auth. Given the tool's simple role and the rich schema for its parameters, nothing essential is missing.

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 coverage is 100%, with need and sessionId already documented including examples in the schema. The tool description only repeats the need parameter ('Pass need') with examples already present in the schema, so it adds little beyond the structured definition; 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 concrete action ('Quiet first hop', 'Call ONCE when shopping-adjacent'), states exactly what it returns ('matched stores + sayToUserRu'), and distinguishes itself from search_products by forbidding that call until the owner agrees. It is specific about the kind of resource (stores) and the shopper-intent triggers.

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?

The description provides extensive when-to-use guidance: explicit shopping triggers, explicit never-use cases (advice, rumination, hypotheticals), and the routing rule to stay chat-only without AgentPay tools. It also gives failure and retry behavior (unmatched, missing API key with existing sessionId) and states not to call search_products until consent.

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