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

Annotations supply only the basic read-only/safe profile; the description adds real behavioral context: invite-link owners get preferredStores + preferredStoreRoutingRu, demoOnly requests must avoid Dixy/Ozerki, and testMode changes both the visible store list and the currency (gray coins). The shopping guardrails ('Never invent a shop, never open a random website to pay') are also useful beyond the annotations. I see no contradiction with readOnlyHint/openWorldHint.

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?

Although longer than a typical tool blurb, every sentence contributes a distinct rule: allowlist boundary, return-field caveat, call triggers, demoOnly behavior, sibling routing, and testMode behavior. It is front-loaded with the core purpose and constraint, and the structure flows from invocation to exclusions. This is dense but not padded.

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?

Covers the important invocation conditions: user phrases, demoOnly mode, testMode, invite-link routing, and the forbidden alternative paths. The main gaps are that the ordinary return shape is not described beyond the special-case fields, and peek_stores is referenced as the alternative but is absent from the provided sibling list. Still, for correctly selecting and calling the tool, the description is nearly 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 already documents both parameters at 100% coverage: need examples «техника» and the peek_stores preference, demoOnly's explicit demo/test-catalog condition and exclusion of live stores. The description reinforces demoOnly with the Dixy/Ozerki caveat, but it doesn't materially alter the meaning of either parameter. 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?

Opens with a concrete verb+resource: 'List stores on this agent's allowlist,' and immediately clarifies the domain constraint ('The agent MUST shop only here'). It also signals what the tool is not by pointing to peek_stores for search-like intents and explicitly excluding search_products for «найди/сравни/подбери». No ambiguity remains about what this specific tool does.

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?

Lists explicit user-language triggers: «магазин», «где можно потратить», «спецмагазин», «тестовый магазин». It gives a precise conditional for demoOnly and an explicit alternative: 'For «найди» / «сравни» / «подбери» call peek_stores first, not this dump and not search_products.' That is exactly the when/when-not/alternatives guidance this dimension asks for.

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