feat: add shared vLLM Responses event contract

.github/workflows/prepare-release-pr.yml

@@ -82,8 +82,15 @@ jobs:
           if dependency_count != 1:
               raise SystemExit("Expected exactly one agentic-core workspace dependency version in Cargo.toml")
 
+          dependency_pattern = (
+              r'(?m)^(vllm-responses = \{ path = "crates/vllm-responses", version = ")[^"]+(" \})$'
+          )
+          text, dependency_count = re.subn(dependency_pattern, rf'\g<1>{version}\g<2>', text, count=1)
+          if dependency_count != 1:
+              raise SystemExit("Expected exactly one vllm-responses workspace dependency version in Cargo.toml")
+
           path.write_text(text)
-          print(f"Updated workspace and agentic-core versions to {version}")
+          print(f"Updated workspace, agentic-core, and vllm-responses versions to {version}")
           PY
 
       - name: Refresh lockfile

.github/workflows/release-crates.yml

@@ -68,14 +68,17 @@ jobs:
             | jq -r '.packages[] | select(.name == "agentic-server-core") | .version')"
           server_version="$(cargo metadata --locked --format-version 1 --no-deps \
             | jq -r '.packages[] | select(.name == "agentic-server") | .version')"
+          responses_version="$(cargo metadata --locked --format-version 1 --no-deps \
+            | jq -r '.packages[] | select(.name == "vllm-responses") | .version')"
 
-          if [ -z "$core_version" ] || [ "$core_version" = "null" ]; then
-            echo "::error::agentic-server-core package not found in workspace metadata"
+          if [ -z "$core_version" ] || [ "$core_version" = "null" ] \
+            || [ -z "$responses_version" ] || [ "$responses_version" = "null" ]; then
+            echo "::error::release package not found in workspace metadata"
             exit 1
           fi
 
-          if [ "$core_version" != "$server_version" ]; then
-            echo "::error::agentic-server-core ($core_version) and agentic-server ($server_version) versions differ"
+          if [ "$core_version" != "$server_version" ] || [ "$core_version" != "$responses_version" ]; then
+            echo "::error::release package versions differ"
             exit 1
           fi
 
@@ -113,7 +116,7 @@ jobs:
           AGENTIC_RELEASE_VERSION: ${{ steps.version.outputs.version }}
         run: |
           set -euo pipefail
-          for crate in agentic-server-core agentic-server; do
+          for crate in vllm-responses agentic-server-core agentic-server; do
             status="$(curl --silent --show-error --output /dev/null --write-out '%{http_code}' \
               --user-agent 'agentic-api-release (https://github.com/vllm-project/agentic-api)' \
               --connect-timeout 10 --max-time 30 \
@@ -159,13 +162,41 @@ jobs:
         if: inputs.dry_run
         run: |
           set -euo pipefail
-          cargo publish --dry-run --locked -p agentic-server-core
-          cargo package --no-verify --locked -p agentic-server \
-            --config 'patch.crates-io.agentic-server-core.path="crates/agentic-server-core"'
+          cargo publish --dry-run --locked -p vllm-responses
+          cargo publish --dry-run --locked -p agentic-server-core \
+            --config 'patch.crates-io.vllm-responses.path="crates/vllm-responses"'
+          cargo publish --dry-run --locked -p agentic-server \
+            --config 'patch.crates-io.agentic-server-core.path="crates/agentic-server-core"' \
+            --config 'patch.crates-io.vllm-responses.path="crates/vllm-responses"'
           echo "Would release commit ${{ steps.target.outputs.sha }}"
           echo "Would create tag ${{ steps.version.outputs.tag }}"
           echo "Would create GitHub release ${{ steps.version.outputs.tag }} with generated notes"
 
+      - name: Publish vllm-responses
+        if: ${{ !inputs.dry_run }}
+        env:
+          CARGO_REGISTRY_TOKEN: ${{ secrets.CARGO_REGISTRY_TOKEN }}
+        run: cargo publish --locked -p vllm-responses
+
+      - name: Wait for vllm-responses index
+        if: ${{ !inputs.dry_run }}
+        run: |
+          set -euo pipefail
+          version="${{ steps.version.outputs.version }}"
+
+          for attempt in {1..30}; do
+            if cargo info "vllm-responses@$version" >/dev/null 2>&1; then
+              echo "vllm-responses $version is available in crates.io index"
+              exit 0
+            fi
+
+            echo "Waiting for crates.io index to expose vllm-responses $version (attempt $attempt/30)"
+            sleep 10
+          done
+
+          echo "::error::vllm-responses $version was not visible in crates.io index in time"
+          exit 1
+
       - name: Publish agentic-server-core
         if: ${{ !inputs.dry_run }}
         env:

ARCHITECTURE.md

@@ -616,12 +616,13 @@ merge the concrete item with its retained fields and buffers. `slot.rs` dispatch
 to those implementations after validating identity and lifecycle. Finalization
 promotes each completed typed item once and preserves validated output-index order.
 
-The pipeline's streaming entry is `process_line(ClassifiedSseLine)`. It normalizes and
-validates a data line, applies the event to the slot keyed by its validated output
-index, and returns at most one validated `EventFrame` for translation. For function
-events, `accumulated_function_call(output_index)` exposes a borrowed typed call and its
-folded arguments. `finish` applies SSE end-of-stream policy; `finalize` preserves the
-status loaded from a complete JSON body.
+The pipeline's HTTP/SSE streaming entry is `process_line(ClassifiedSseLine)` in
+`source.rs`; native adapters enter through `process_inference_event(InferenceEvent)`
+in `native.rs`. Both paths materialize the same internal frame and apply the same
+strict lifecycle validation before translation. For function events,
+`accumulated_function_call(output_index)` exposes a borrowed typed call and its folded
+arguments. `finish` applies SSE end-of-stream policy; `finalize` preserves the status
+loaded from a complete JSON body.
 
 When adding an output-item kind, extend its typed construction and completion logic in
 `types/io/output.rs`, the variants and exhaustive dispatch in `accumulator/active.rs`,

CHANGELOG.md

@@ -4,6 +4,11 @@ All notable changes to Agentic API are documented here.
 
 ## [Unreleased]
 
+### Added
+
+- Added the published `vllm-responses` crate: a transport-independent typed
+  inference-event contract for vLLM and Agentic API integrations (#359).
+
 ## [0.8.0] - 2026-09-19
 
 ### Added

Cargo.toml

@@ -17,6 +17,7 @@ pedantic = { level = "warn", priority = -1 }
 
 [workspace.dependencies]
 agentic-core = { package = "agentic-server-core", path = "crates/agentic-server-core", version = "0.8.0" }
+vllm-responses = { path = "crates/vllm-responses", version = "0.8.0" }
 async-stream = "0.3"
 axum = { version = "0.8", features = ["ws"] }
 either = "1"

crates/agentic-server-core/Cargo.toml

@@ -19,6 +19,7 @@ default = []
 openapi = ["dep:utoipa"]
 
 [dependencies]
+vllm-responses.workspace = true
 utoipa = { workspace = true, optional = true }
 
 async-stream.workspace = true

crates/agentic-server-core/src/executor/accumulator/mod.rs

@@ -36,7 +36,11 @@ use identity::{invalid_lifecycle, invalid_lifecycle_or_id, invalid_stream, item_
 mod completion;
 mod details;
 mod json;
+mod native;
+#[cfg(test)]
+mod native_tests;
 mod slot;
+mod source;
 
 use active::ActiveItem;
 use slot::{OutputIndex, SlotMap, SlotState};
@@ -296,27 +300,6 @@ impl ResponseAccumulator {
         Ok(acc)
     }
 
-    /// Processes pre-collected raw SSE lines synchronously.
-    ///
-    /// Useful when lines have already been buffered (e.g. replaying a recorded stream).
-    /// Prefer [`from_stream`](Self::from_stream) for live async streams.
-    /// Malformed data frames are skipped for compatibility.
-    ///
-    /// # Errors
-    /// Returns [`ExecutorError::InvalidRequest`] when repeated authoritative
-    /// output-item content conflicts with the previously accumulated value.
-    pub fn from_sse_lines(
-        lines: impl IntoIterator<Item = String>,
-        conversation_id: Option<&str>,
-    ) -> ExecutorResult<Self> {
-        let mut acc = Self::new(uuid7_str("resp_"), conversation_id.map(str::to_string));
-        for line in lines {
-            let _ = acc.process_line(SseLine::parse(&line))?;
-        }
-        acc.finalize_all()?;
-        Ok(acc)
-    }
-
     /// Finalizes all streaming items in upstream `output_index` order.
     pub(crate) fn finalize_all(&mut self) -> ExecutorResult<()> {
         self.output
@@ -335,8 +318,7 @@ impl ResponseAccumulator {
             }
             return Ok(None);
         };
-        let disposition = self.process_normalized_event(&frame)?;
-        Ok(disposition.into_frame(frame))
+        self.process_event_frame(frame)
     }
 
     fn process_normalized_event(&mut self, frame: &EventFrame) -> ExecutorResult<EventDisposition> {