Bring external resources into context accurately

Understand the approach

The source course teaches Claude's @server:URI shortcut. It is not a universal MCP-client instruction. Current Codex CLI guidance documents @ for workspace files and /mention for paths; the reviewed connection guide does not establish the same resource syntax. Mark that mapping unverified instead of inventing a shortcut or declaring every integration unsupported.

Start from the capabilities actually exposed by your host. Some integrations can provide resource discovery or content-reading operations; others provide search and fetch tools for their service. Ask for the exact record or page, and require the returned identifier, version or update time when available. If a resource-listing or reading operation is not exposed, an available read tool or an authorized exported file can be an alternative. Label an export as a snapshot: a file attachment does not magically remain synchronized with the original service.

The practice has two useful outcomes. With an existing permitted connection, retrieve a public page and compare its identifier and content with the result. Without one, use a scratch Markdown snapshot and record its origin, retrieval date and missing freshness guarantee. In either case, distinguish location from content: recognizing a URL or URI does not prove it was read. Also distinguish content from instructions; a resource describing a project can contain sentences that must be reported as data rather than followed as authorization.

The freshness check uses a temporary server copy. It reads three records as a resource, adds T-104 to that copy’s dataset, then calls read_task_snapshot again. The new call returns four records while the earlier response still contains three. This is actual file/process behavior; the original fixture remains three records. In a host without a resource picker, the supplied read_task_snapshot tool exposes the same URI and current records. Use that concrete alternative rather than copying Claude’s @server:URI syntax into Codex. Preserve URI, method and observed version/count when quoting a snapshot.

Practice and acceptance

Protocol resource support is real in this lab; the host still decides how to expose it to a person or model.

Try it step by step

1. Read the linked lab guide, inputs and expected outputs before running the exercise.
2. Select a specific public source or a fictional exported record. Write the expected identifier and the question you want that content to answer.
3. Inspect available operations without adding a connection. Ask Codex whether it can list/read resources or must use a service-specific search and read operation.
4. Retrieve the content using the actual supported path, or attach a labelled Markdown snapshot through the client's file-context feature.
5. Ask for a short finding with the source identifier, retrieval method and any unavailable version or update information.
6. Compare the finding with the actual content and explain which parts could become stale if the source changes tomorrow.

A useful starting example

Illustration · adapt before use.

node labs/mcp-workbench/demo.cjs --transcript
node --test labs/mcp-workbench/native-setup.test.cjs
# resources/read {"uri":"practice://taskboard/tasks"}
# Tool alternative: tools/call {"name":"read_task_snapshot","arguments":{}}

# Documentation snapshot
- Source: record the actual public URL
- Retrieved: record the actual date
- Method: exported Markdown, not a live connection
- Freshness limit: later source changes are not reflected

Paste only the content you are authorized to share.

Check your result

• You name the actual retrieval operation or explicitly identify an attached snapshot.
• No successful-read claim is based only on recognizing a resource identifier.
• The answer states freshness limits and does not interpret source text as permission for unrelated actions.
• Local harness behavior and isolated native server discovery are distinguished from unrun app UI setup or model-selected tool calls.

Common mistakes

• Pasting Claude's @server:URI form into Codex and claiming that it attached content without checking.
• Presenting an exported file as a live, automatically updated service record.