teos_how_to_buy

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

With no annotations, the description must carry the behavioral burden. It usefully discloses that the call is "Free" and that the output is plain-language instructions, but says nothing about permissions, rate limits, or what the instructions actually cover. For a zero-parameter informational tool this is adequate but thin.

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 the deliverable before the cost note and the trigger condition. No filler, though "Free." as a standalone fragment is slightly clipped.

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 does at least characterize the return value as plain-language payment instructions covering x402/USDC. For a simple no-param help tool this is nearly sufficient, though it could briefly indicate what topics the instructions span.

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 takes zero parameters, so the schema imposes no semantic burden and the baseline of 4 applies. The description adds no parameter detail, which is correct since none exist.

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 states a specific deliverable: plain-language instructions for paying a TEOS tool via x402 with USDC. The agent can tell this is an informational/how-to tool rather than an action tool. It does not explicitly contrast itself with the sibling teos_catalog, which also relates to TEOS tools, so it stops short of a 5.

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?

"Use when your agent needs to know how to buy and call a TEOS tool" gives an explicit trigger condition for invoking it. There are no stated exclusions or named alternatives (e.g., teos_catalog for discovery), so it is clear context without routing guidance.

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