list_credentialsCredentials in your n8n -- id, name and type only, never secret values.
Reference one in a node as {"<type>": {"id": "...", "name": "..."}}.
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": "list_credentials"
}
}| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and destructiveHint=false, but the description adds genuinely new and important behavioral context: secret values are never returned, and the exact shape in which a credential is referenced inside a node. This is exactly the sort of safety/return-content detail annotations cannot convey. It stops short of 5 only because it doesn't mention auth requirements or whether the list is scoped/paginated.
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?
Two compact sentences with no filler, and the key constraint (never secret values) is front-loaded. The second sentence is slightly tangential to 'listing' but earns its place by telling the agent how to consume the result.
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 carries the return-value burden and handles it by naming the exact fields returned. For a zero-parameter read tool this is largely sufficient, with only minor gaps around scoping (all credentials vs. a subset) and any pagination.
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 there is nothing for the description to disambiguate; baseline for 0 params is 4. The schema coverage is 100% and the object is empty, so no further parameter explanation is needed.
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 definition clearly identifies the resource (n8n credentials) and explicitly enumerates what is returned — id, name, and type only. No other sibling tool touches credentials, so differentiation is implicit, but an agent can tell exactly what this yields. The verb 'list' is carried by the name/title rather than the description body, which keeps it just 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?
There is no explicit when-to-use or when-not-to-use statement, and no named alternative. However, the second sentence ('Reference one in a node as ...') implicitly tells the agent the purpose: fetching credential IDs/names to embed in workflow node configuration. That is meaningful but leaves callers to infer the trigger condition.
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.