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

Beyond the readOnlyHint annotation, the description discloses important behavioral details: returned delivery data excludes raw addresses, the server attaches the home address on create_purchase, preferredStoreRoutingRu should change product search behavior, and sessionId-based auth needs a retry rather than re-initiating agent link. These are non-obvious behaviors an agent needs to know.

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 every clause serves a purpose: return-content inventory, trigger phrases, routing precedence, create_purchase caveat, auth retry, and prohibitions. It is front-loaded with the most important information and contains no filler or tautology.

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?

For a zero-required-parameter retrieval tool with no output schema, the description fully compensates by listing the returned fields, when to invoke it, how to use its output, and relevant auth behavior. An agent has enough context to call the tool correctly and interpret the result.

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?

The only parameter, sessionId, already has 100% schema description coverage. The description restates when to pass it ('If AGENTPAY_API_KEY required and you already have sessionId from this chat: pass sessionId and retry'), but it does not materially add semantics beyond the schema. 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 opens with a specific verb and resource: 'Get hard + soft spending policies' and enumerates the exact fields returned (allowlist, forbidden categories, confirmation mode, preference weights, etc.). It also implicitly distinguishes itself from siblings by referencing search_products and create_purchase in the workflow, so an agent can tell what this tool is for.

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 gives explicit trigger conditions: 'Call before a surprise buy or when the user says «правила трат», «политика», «что можно покупать», «на удачу».' It also provides routing guidance ('follow it before search_products'), caveats for create_purchase, sessionId retry behavior, and explicit prohibitions. This leaves little ambiguity about when and how to use the tool.

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