MCP Resources provide a browsable content catalog. The agent can list what’s available and read specific items — without making exploratory tool calls. This is the right primitive for content directories, knowledge bases, and data catalogs.
Resources vs Tools for content
500 support articles as MCP Resources: the agent calls resources/list to see available articles, then resources/read to fetch specific ones. No tool selection confusion, no 500-tool explosion.
500 support articles as Tools: creating a tool per article (500 tools) destroys selection reliability. Even a single search tool requires the agent to know what to search for.
Resources advantage: the agent can browse what’s available without knowing in advance what exists. This is especially useful for discovery — the agent sees the catalog and makes informed decisions about what to read.
When to use each
Resources — content that the agent browses and reads: knowledge bases, document collections, configuration catalogs, data schemas. Read-only, catalog-based access.
Tools — actions that change state or require parameters: create issue, process refund, run query. Executable operations with side effects.
The dividing line is the same as F3.2: Resources are for observation (reading), Tools are for action (doing).
Resources reduce tool count
Every piece of content exposed as a Resource doesn’t add to the tool count. An agent with 3 tools and access to 500 Resources via MCP still has just 3 tools for selection purposes. The Resources are accessed through the MCP resource protocol, not through tool calls.
One-liner: Use MCP Resources for browsable content catalogs (knowledge bases, document collections) and Tools for actions — Resources don’t add to tool count and enable discovery without requiring the agent to know what to search for.