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

With no annotations provided, the description carries the full burden of behavioral disclosure. It transparently states the credential's temporary nature (24h), that it settles nothing (simulated payments), that it works only on the demo store, and that no human login is involved. This covers the key behavioral aspects an agent needs to know before invoking the tool.

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 concise, consisting of three sentences that front-load the core purpose and then provide usage and limitations. Every sentence adds value with no redundancy or unnecessary detail. It is well-structured for quick agent comprehension.

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 that the tool has an output schema (not shown here but indicated), the description does not need to explain the return format. It covers the purpose, usage, validity, scope, and caveats. For a zero-parameter, self-contained tool, the description is complete and sufficient for an agent to use it correctly.

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 tool has zero parameters, and the schema confirms this. The description does not need to explain parameter semantics because none exist. The baseline for 0 parameters is 4, and since there is nothing to add, this score 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 clearly identifies the tool's purpose: fetching a temporary sandbox credential for the demo store. It uses a specific verb ('Get') and resource ('temporary sandbox credential') and distinguishes itself from sibling tools that handle carts, checkout, and product browsing. The 24-hour validity and demo-only scope are explicitly stated, leaving no ambiguity about what the 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?

The description provides explicit instructions on how to use the credential: either as an Authorization: Bearer header or as the agent_key argument, with a clear caveat for clients that cannot set headers. It also sets expectation that payments are simulated and the credential only works on the demo store. While it doesn't name alternatives (none exist among siblings), the usage context is fully specified.

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