Search OP-verified merchants by rail, chain, category, agent-callable tier, trust tier, and free text. Ranked by trust tier then verification recency.
| Name | Required | Description | Default |
|---|---|---|---|
| rail | No | ||
| chain | No | ||
| limit | No | ||
| query | No | ||
| category | No | ||
| accepts_usdc | No | ||
| trust_tier_min | No | ||
| agent_callable_tier | No |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full transparency burden. It adds useful behavioral context by specifying that results are ranked by trust tier then verification recency, and that only OP-verified merchants are included. However, it does not disclose other potential behaviors such as pagination, rate limits, or authentication requirements.
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 two sentences, front-loaded with the primary verb and resource, and every word adds value. There is no fluff or repetition.
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 the complexity (8 parameters, no output schema, no annotations), the description provides a solid high-level overview and even mentions the ranking order, but it is not fully complete. It omits explanations of the limit parameter, accepts_usdc filter, and what 'OP-verified' entails, which could be important for an agent to use the tool correctly.
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 input schema has 8 parameters with 0% description coverage, but the description enumerates the key filter dimensions (rail, chain, category, agent-callable tier, trust tier, free text), which maps to most parameters. However, it does not explicitly explain the meaning of 'limit', 'accepts_usdc', or clarify that 'trust tier' refers to 'trust_tier_min' (a minimum filter). The enum values in the schema help fill in some gaps, but the description only partially compensates for the lack of parameter-level documentation.
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 has a specific verb ('Search') and resource ('OP-verified merchants'), and clearly lists the available filters (rail, chain, category, agent-callable tier, trust tier, free text). It distinguishes itself from sibling tools like get_merchant by indicating a search over multiple criteria rather than fetching a single merchant.
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 clearly implies when to use the tool: when looking for merchants matching any of the listed filters. It provides a clear context for use (search by various criteria), but it does not explicitly exclude alternatives or mention when to prefer get_merchant for a single merchant lookup.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
Each tool has a distinct role: retrieving a merchant, listing taxonomies, searching, verifying endpoints, and checking credentials. No two tools overlap in purpose, so an agent can easily select the right one.
Most tools follow a clear verb_noun snake_case pattern (get_merchant, list_categories, list_rails, search_merchants, verify_payment_endpoint). The only exception is 'whoami', a standard command-style name that is still unambiguous and consistent with the lowercase underscore convention.
With 6 tools, the server is well-scoped for a directory service. Each tool addresses a necessary aspect of merchant discovery, lookup, verification, and authentication without unnecessary bloat or gaps.
The tool surface covers the full lifecycle for an agent using this directory: listing taxonomies, searching merchants, retrieving merchant details, verifying payment endpoints, and checking credentials. There are no obvious missing operations for the stated purpose.