SouthPow API

buy_yields_protocol_invesco-ustb

Paid. Live DeFi yields for invesco-ustb: its pools across chains with APY, TVL, 7d APY change (DefiLlama data). $0.002 USDC on Base or Solana. No account, no API key. Failed calls not charged. URL https://southpow.media/v1/yields/protocol/invesco-ustb.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "buy_yields_protocol_invesco-ustb"
  }
}

Input Schema

Name	Required	Description
`sort`	No	tvl (default) or apy
`limit`	No	Rows, 1-100 (default 20)
`min_tvl_usd`	No	Minimum pool TVL in USD (default 100000)

Schema Changelog

Changes observed during successful MCP inspections.

AddedNov 4, 2026

TDQS

A3.8/5.0

Behavior4/5

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

With no annotations, the description carries the full burden and does well: it discloses that the call is paid, the exact price and payment chains, that no account or API key is needed, and that failed calls are not charged. What it omits is rate limits, pagination/default behavior beyond the schema, and any note on data freshness beyond 'Live'.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Extremely dense and front-loaded: 'Paid.' is the first token, followed by the data scope, then price/access terms, then the endpoint URL. Every sentence carries information an agent cannot get from the schema, and there is no filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a three-optional-parameter tool with no output schema, the description covers the data returned (pools across chains, APY, TVL, 7d change), cost, payment options, and failure pricing. Missing only response shape/depth and freshness cadence, which are minor for a paid single-endpoint wrapper.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%: sort, limit, and min_tvl_usd all carry their own descriptions and defaults in the schema. The description adds no parameter-level meaning (e.g., how sorting interacts with min_tvl_usd filtering), so the baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

A specific verb and resource are stated: live DeFi yields for the invesco-ustb protocol, including the returned fields (APY, TVL, 7d APY change) and the data source (DefiLlama). It is scoped precisely to one protocol, so an agent can separate it from buy_yields_chain_* tools. However, it never distinguishes itself from the near-identical sibling buy_yields_token_ustb, leaving a protocol-vs-token ambiguity unresolved.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The scope ('Live DeFi yields for invesco-ustb: its pools across chains') implies when the tool applies, and 'Paid. ... $0.002 USDC on Base or Solana' implies a cost gate before calling. There is no explicit when-to-use or when-not-to-use statement, and no routing to alternatives such as the chain- or token-level yields tools.

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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