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

With no annotations, the description carries the full burden. It discloses that the tool is model-agnostic, requires no authentication, always returns HTTP 200, and returns a specific upgrade ladder structure. This is comprehensive for a read-only tool, though it could mention idempotency or lack of side effects more explicitly.

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 well-structured with a clear 'WHEN TO USE' section, a list of returned items, and the return object keys. It is mostly concise, though the phrase 'Model-agnostic: works identically regardless of which AI model consumes it' adds extra context that could be considered slightly verbose, but remains valuable.

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 no parameters and no output schema, the description fully explains the return format (listing each key and its meaning), states no authentication required, and notes always returns 200. It provides complete context for an AI agent to understand what the tool does and how to interpret its output.

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?

There are zero parameters, and schema coverage is 100% (empty schema). The description adds no parameter information, but with no parameters, the baseline is 4. It does add value by explaining the return structure and behavior beyond the schema.

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 available payment and authentication options for accessing live market data, using a specific verb ('Returns') and resource. It distinguishes itself from sibling tools (get_market_schedule, get_market_status, list_exchanges) by focusing on payment and authentication rather than market scheduling or status.

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 explicitly provides a 'WHEN TO USE' section, stating to use this tool when needing to understand authentication or payment before making requests that require a key or payment. This clearly guides when to use this tool versus alternatives, though it does not explicitly exclude other contexts.

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