Execution and Context in Model Context Protocol

Lessons in this section

1. Tool Call Execution

   The steps of an MCP tool call: catalog, inspection, selection, approval, tools/call and results, with content blocks, outputSchema and structuredContent, isError, progress and cancellation.

2. Tool Schema Validation

   Validating MCP tool calls on client and server: missing, wrong-type, out-of-range and unknown arguments; schema design; error frames; output validation; and partial results.

3. Resource URIs

   Resource URI parts and schemes, path and query templates, text and base64 contents with MIME types, the resource methods, and freshness with ttlMs, cacheScope and update notices.

4. Resource Context Assembly

   Turning MCP resources into safe, useful context: source tags, freshness, field filtering, truncation, redaction, read-only enforcement and scope validation.