René's URL Explorer Experiment

Title: Pass InputRequiredResult through the MCPServer prompt and resource pipelines by maxisbey · Pull Request #3020 · modelcontextprotocol/python-sdk · GitHub

Open Graph Title: Pass InputRequiredResult through the MCPServer prompt and resource pipelines by maxisbey · Pull Request #3020 · modelcontextprotocol/python-sdk

X Title: Pass InputRequiredResult through the MCPServer prompt and resource pipelines by maxisbey · Pull Request #3020 · modelcontextprotocol/python-sdk

Description: Motivation and Context input-required-result-non-tool-request was the last waived server conformance scenario: at 2026-07-28 a server MAY answer prompts/get and resources/read with an InputRequiredResult (SEP-2322 multi-round-trip requests), but only the tools/call pipeline passed one through from MCPServer — the prompt pipeline silently coerced it into a text message and the resource pipeline had no path for it. The low-level Server, the per-version result surfaces, and the client auto-loop (#2998) already supported all three methods, so this closes the gap at the one remaining tier, mirroring the tools pass-through from #2974: Prompt.render / MCPServer.get_prompt pass an InputRequiredResult returned by an @mcp.prompt() function through unchanged; the retry's answers arrive on ctx.input_responses, with ctx.request_state carrying the echoed state. ResourceTemplate.create_resource / MCPServer.read_resource do the same for @mcp.resource() template functions. Static resource functions can never read the retry (they take no Context), so FunctionResource.read now rejects an InputRequiredResult loudly instead of JSON-dumping it as resource text. Context.read_resource stays a pure content reader: an InputRequiredResult from a template raises a clear RuntimeError there. A handler that wants to receive and forward one as its own result calls MCPServer.read_resource(uri, context) directly, which carries the union. Era handling needed zero new code: the per-version result surfaces already reject the frame toward pre-2026 sessions with -32603, exactly as for tools. The everything-server gains the test_input_required_result_prompt fixture the scenario drives, and the waiver is removed from both expected-failures files — both server conformance baselines are now empty. How Has This Been Tested? The target scenario passes locally at the pinned harness (2/2 checks; previously failed round 1). All three CI server conformance legs run locally at the pin with the emptied baselines: active 42/42, draft 71/71, 2026-07-28 100/100 — zero failures, no stale entries. Full suite at 100% branch coverage. New tests cover the prompt/resource round trips through an in-memory Client, the seam pass-throughs (identity), both ctx.read_resource arcs, the static-resource rejection, and the legacy-session -32603 posture for both methods. mkdocs build --strict passes with the new docs section and runnable example. Coverage note: the scenario exercises prompts/get only — no conformance scenario currently drives resources/read returning InputRequiredResult, so the resource side is proven by the SDK test suite alone. Worth adding a scenario in the conformance repo. Breaking Changes Type-level, documented in docs/migration.md: MCPServer.get_prompt() / read_resource() (and Prompt.render() / ResourceTemplate.create_resource()) now return ... | InputRequiredResult; direct callers narrow with isinstance. ctx.read_resource() is unchanged — it still returns content, and now raises a clear RuntimeError if the resource requests input (forward via MCPServer.read_resource(uri, context) instead). Types of changes Bug fix (non-breaking change which fixes an issue) New feature (non-breaking change which adds functionality) Breaking change (fix or feature that would cause existing functionality to change) Documentation update Checklist I have read the MCP Documentation My code follows the repository's style guidelines New and existing tests pass locally I have added appropriate error handling I have added or updated documentation as needed Additional context Part of #2891. With this change, .github/actions/conformance/expected-failures.yml and expected-failures.2026-07-28.yml are both fully empty — every scenario in the pinned conformance harness passes against the SDK with no waivers. AI Disclaimer

Open Graph Description: Motivation and Context input-required-result-non-tool-request was the last waived server conformance scenario: at 2026-07-28 a server MAY answer prompts/get and resources/read with an InputRequired...

X Description: Motivation and Context input-required-result-non-tool-request was the last waived server conformance scenario: at 2026-07-28 a server MAY answer prompts/get and resources/read with an InputRequired...

Opengraph URL: https://github.com/modelcontextprotocol/python-sdk/pull/3020

X: @github

direct link

Domain: github.com

Links:

Viewport: width=device-width