get_treasury_yield_by_dateReturns the 30-year US Treasury yield for a specific date. Business days only. Use YYYY-MM-DD format. Price: $0.01 USDC per call via x402 (Base or Solana).
| Name | Required | Description | Default |
|---|---|---|---|
| date | Yes | Date in YYYY-MM-DD format, e.g. 2026-05-09 |
Changes observed during successful MCP inspections.
Input schema / properties / date / descriptionPrevious value: -"Date in YYYY-MM-DD format e.g. 2026-05-09"New value: +"Date in YYYY-MM-DD format, e.g. 2026-05-09"Output schema / (root)Previous value: -{
- "$schema": "http://json-schema.org/draft-07/schema#",
- "additionalProperties": false,
- "properties": {
- "date": {
- "description": "Date of the observation (YYYY-MM-DD)",
- "type": "string"
- },
- "yield_percent": {
- "description": "30-year Treasury yield as a percentage",
- "type": "string"
- }
- },
- "required": [
- "yield_percent",
- "date"
- ],
- "type": "object"
-}New value: +nullDoes the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover read-only, idempotent, open-world and non-destructive, so the bar is low. The description still adds two traits not in the annotations: business-day-only data availability and a $0.01 USDC per-call x402 payment requirement, the latter being operationally critical before invoking.
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?
Three short sentences, front-loaded with what is returned, then the constraint, then the cost. Nothing is wasted and the payment caveat is not buried.
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?
With no output schema, the description should say more about the response: units (percentage points vs basis points), and especially what happens when a weekend/holiday date is supplied. Safety and cost are covered, but the failure mode for non-business days is left ambiguous.
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 coverage is 100% and the single `date` parameter is already documented with format and an example in the schema. The description restates the YYYY-MM-DD format and adds the business-day restriction on valid values, but adds no new semantics beyond that.
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?
States a specific verb and resource with scope qualifiers ('30-year US Treasury yield', 'for a specific date'), which implicitly separates it from get_treasury_yield_current and get_yield_curve. It never names a sibling explicitly, so the differentiation is inferred rather than stated.
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?
'Business days only' and 'Use YYYY-MM-DD format' are real usage constraints, but there is no guidance on when to pick this over get_treasury_yield_current or get_yield_curve. The agent must infer the historical-single-date use case from the name alone.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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