read_store_guide

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

Annotations already declare readOnlyHint and idempotentHint, so the bar is lower. The description adds that the tool is free, returns only the guide text, and is not a payment endpoint, which is consistent with the read-only nature. It doesn't add extra behavioral details, but for a simple read the provided context is sufficient.

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 two sentences, front-loaded with a clear metaphor, and includes all essential information without waste. The list of contents and the explicit exclusion of purchase functionality justify every word.

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?

Given the tool's simplicity (0 params, output schema exists), the description is complete. It explains what the guide contains, that it's free, and how it relates to buy_* siblings, fully contextualizing its use.

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 input schema has zero parameters, so the schema covers everything. The description adds no parameter-specific info, which is appropriate. Baseline for 0 params is 4.

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 clearly states the tool returns the store's guide as text, listing contents (menu, prices, payment info, free shelf, promises). It explicitly distinguishes itself from purchase tools, making its purpose unambiguous and well-differentiated from siblings.

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 explicitly says when NOT to use it (for purchasing/payment) and directs the agent to call a buy_* tool with x402 payment in _meta. It also notes it is free, implying no payment required, providing clear usage context and an explicit alternative.

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