POST /api/run_sse rejects functionCallEventId field sent by adk-web dev-ui

[st699pic]

Bug Description

When using the ADK dev-ui (adk-web) to respond to a long-running function call (e.g., OAuth authorization or human-in-the-loop confirmation), the request to POST /api/run_sse fails with:

failed to decode request body: failed to decode request: json: unknown field "functionCallEventId"

Root Cause

The dev-ui frontend (bundled in cmd/launcher/web/webui/distr/main-*.js) sends functionCallEventId in the request body when resuming a long-running function call:

// From dev-ui bundle (minified)
let e = {
  appName: this.appName,
  userId: this.userId,
  sessionId: this.sessionId,
  newMessage: { role: "user", parts: [{ functionResponse: {...} }] },
  functionCallEventId: this.functionCall.functionCallEventId  // ← this field
};
this.agentService.runSse(e).subscribe(...)

However, the Go backend RunAgentRequest struct (server/adkrest/internal/models/runtime.go:23) does not define this field:

type RunAgentRequest struct {
    AppName    string          `json:"appName"`
    UserId     string          `json:"userId"`
    SessionId  string          `json:"sessionId"`
    NewMessage genai.Content   `json:"newMessage"`
    Streaming  bool            `json:"streaming,omitempty"`
    StateDelta *map[string]any `json:"stateDelta,omitempty"`
}

And the decoder at server/adkrest/controllers/runtime.go:240 uses DisallowUnknownFields():

func decodeRequestBody(req *http.Request) (models.RunAgentRequest, error) {
    var runAgentRequest models.RunAgentRequest
    d := json.NewDecoder(req.Body)
    d.DisallowUnknownFields()  // ← rejects functionCallEventId
    ...
}

Expected Behavior

The /run_sse endpoint should accept the functionCallEventId field (either by adding it to the struct or by removing strict unknown-field validation), allowing the dev-ui long-running function call flow to work end-to-end.

Steps to Reproduce

1. Configure an agent with a long-running tool (e.g., one requiring user confirmation or OAuth)
2. Start the agent with adk web or using full.NewLauncher()
3. Send a message that triggers the long-running tool
4. In the dev-ui, respond to the function call confirmation dialog
5. Observe the 400 error: json: unknown field "functionCallEventId"

Environment

• ADK Go version: v1.4.0 (latest)
• Dev-UI: bundled version in cmd/launcher/web/webui/distr/

Suggested Fix

Add FunctionCallEventId to the RunAgentRequest struct:

type RunAgentRequest struct {
    AppName             string          `json:"appName"`
    UserId              string          `json:"userId"`
    SessionId           string          `json:"sessionId"`
    NewMessage          genai.Content   `json:"newMessage"`
    Streaming           bool            `json:"streaming,omitempty"`
    StateDelta          *map[string]any `json:"stateDelta,omitempty"`
    FunctionCallEventId string          `json:"functionCallEventId,omitempty"`
}

[indurireddy-TF]

Hi @st699pic I have successfully reproduced this bug locally using v1.4.0 with a tool requiring human confirmation (RequireConfirmation: true).

Upon clicking the Confirm button in the Dev-UI, the subsequent POST request to /api/run_sse fails with a 400 Bad Request and the error:
failed to decode request body: failed to decode request: json: unknown field "functionCallEventId"

This is indeed a valid bug caused by the backend's strict JSON decoding configuration (DisallowUnknownFields()) rejecting the functionCallEventId sent by the frontend, which is missing from the RunAgentRequest struct in server/adkrest/internal/models/runtime.go.

[indurireddy-TF]

Applied the proposed fix locally by adding the FunctionCallEventId field to the RunAgentRequest struct in server/adkrest/internal/models/runtime.go:

After rebuilding and running the agent with this change, the manual confirmation flow completes successfully. The backend decodes the payload, executes the tool, and successfully returns the response to the Dev-UI without throwing the 400 error.

[pallat]

Confirming this on v1.4.0 — independently reproduced while building a
teaching example. All three confirmation styles are affected
(RequireConfirmation: true, RequireConfirmationProvider, and manual
ctx.RequestConfirmation()), since they all surface the same
adk_request_confirmation long-running call.

Root cause matches the report: the bundled web UI POSTs functionCallEventId
in the /api/run_sse body, but RunAgentRequest
(server/adkrest/internal/models/runtime.go) has no such field, and the
controller decodes with DisallowUnknownFields()
(server/adkrest/controllers/runtime.go:239-241) → HTTP 400, so the confirmed
tool never runs.

Minimal repro via curl:

# WITHOUT functionCallEventId → 200, tool runs
curl -s -X POST localhost:8080/api/run -H 'Content-Type: application/json' -d '{
  "appName":"A","userId":"user","sessionId":"S",
  "newMessage":{"role":"user","parts":[{"functionResponse":{
    "id":"<adk_request_confirmation id>","name":"adk_request_confirmation",
    "response":{"confirmed":true}}}]}}'

# WITH functionCallEventId (what the UI sends) → 400
#   json: unknown field "functionCallEventId"

Workaround for anyone blocked until #977 lands: send the confirmation via
/api/run without functionCallEventId (look up the pending
adk_request_confirmation id from the session, POST {"confirmed": true|false}).