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

With no annotations, the description carries the behavioral disclosure burden. It explicitly reveals the most important quirk: the tool returns a payment requirement until a payment/bundle_token/api_key is supplied. It also discloses cost and the broad shape of returned data. It stops short of rate limits or exact response contracts, but the core gate behavior is transparent.

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 compact and front-loads the cost and endpoint, followed by data scope and authentication behavior. Every sentence adds information, except possibly 'Verdict-shaped output', which is ambiguous and contributes little without elaboration.

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 there is no output schema and no annotations, the description should fully explain both return behavior and invocation details. It covers the data categories and auth options, but 'verdict-shaped output' is underspecified, and the relationship between a `payment` header and the schema's `payment` property is unclear. The tool is selectable, but not fully invocable without inference.

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 description coverage is 0%, so the description must compensate, and it mostly does. It explains the semantic roles of all three parameters: payment, prepaid bundle_token, and free-tier api_key, including how to obtain a free key via get_free_api_key. It does not specify formats or whether these are headers versus input properties, but the purpose of each parameter is clear.

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 resource: 'Stellar on-chain pulse' and names the data areas delivered (ledger health, XLM supply stats, 1h XLM/USDC SDEX trade statistics). It is specific enough to distinguish from sibling tools like get_xlm_sentiment or get_xlm_quote, though 'Verdict-shaped output' is vague and weakens precision.

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?

There is no explicit guidance about when to choose this tool over siblings, no exclusions, and no mention of the alternatives for sentiment or quotes. The description only provides authorization preconditions ('PAID $0.10 per call', needing payment, bundle_token, or api_key), which is usage context but not tool-selection guidance.

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