{"record":{"id":"259644968bdc81fb","repo":"xai-org/grok-build","slug":"response-parse-error-e","errorCode":null,"errorMessage":"response parse error: {e}","messagePattern":"response parse error: (.+?)","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"crates/codegen/xai-grok-pager/src/worktree_cmd/mod.rs","lineNumber":144,"sourceCode":"}\n/// ACP extension responses are wrapped in `{ \"result\": T, \"error\": ... }`.\n#[derive(serde::Deserialize)]\nstruct ExtEnvelope<T> {\n    result: Option<T>,\n    error: Option<serde_json::Value>,\n}\nasync fn ext_call<T: serde::de::DeserializeOwned>(\n    tx: &xai_acp_lib::AcpAgentTx,\n    method: &str,\n    params: &impl serde::Serialize,\n) -> Result<T> {\n    let req =\n        ext_request(method, params).map_err(|e| anyhow::anyhow!(\"failed to build request: {e}\"))?;\n    let resp = acp_send(req, tx)\n        .await\n        .map_err(|e| anyhow::anyhow!(\"{e}\"))?;\n    let envelope: ExtEnvelope<T> = serde_json::from_str(resp.0.get())\n        .map_err(|e| anyhow::anyhow!(\"response parse error: {e}\"))?;\n    if let Some(err) = envelope.error {\n        bail!(\"ACP error: {err}\");\n    }\n    envelope\n        .result\n        .ok_or_else(|| anyhow::anyhow!(\"ACP response missing result field\"))\n}\nasync fn cmd_list(\n    tx: &xai_acp_lib::AcpAgentTx,\n    repo: Option<String>,\n    types: Vec<String>,\n    json: bool,\n    all: bool,\n) -> Result<()> {\n    let records: Vec<WorktreeRecord> = ext_call(\n        tx,\n        \"x.ai/git/worktree/list\",\n        &serde_json::json!({","sourceCodeStart":126,"sourceCodeEnd":162,"githubUrl":"https://github.com/xai-org/grok-build/blob/bc7f02eddd3d84085849dc19ed216f11c23b0571/crates/codegen/xai-grok-pager/src/worktree_cmd/mod.rs#L126-L162","documentation":"Raised by `ext_call` when the ACP response body received from the agent cannot be parsed into the expected `ExtEnvelope<T>` wrapper via serde_json. This means the reply string is not valid JSON or its shape does not match the envelope (missing/misspelled fields, wrong result payload type). It indicates a protocol mismatch between the CLI's expected schema and what the agent actually returned.","triggerScenarios":"The ACP agent returns malformed or non-JSON text on the wire; the agent returns a valid envelope but the embedded `result` does not deserialize into the caller's generic T; a schema/version drift between CLI and agent changes field names or types.","commonSituations":"Agent upgraded to a newer ACP extension schema while the CLI is older (or vice versa); agent returns an error body without the envelope structure; a proxy/logging layer corrupts the response string.","solutions":["Log the raw `resp.0` string to see exactly what came back and compare with the expected ExtEnvelope schema.","Verify CLI and agent versions match and speak the same ACP extension schema.","Check that the generic T used at each call site matches the actual result payload type for that method.","Fix the Deserialize impl for T (e.g. make new fields #[serde(default)], rename fields to match the agent's output)."],"exampleFix":"// before\n#[derive(Deserialize)]\nstruct WorktreeInfo { path: String, branch: String }\n// after\n#[derive(Deserialize)]\nstruct WorktreeInfo {\n    path: String,\n    #[serde(default)]\n    branch: Option<String>, // tolerate agents that omit the field\n}","handlingStrategy":"try-catch","validationCode":null,"typeGuard":"fn is_valid_envelope(raw: &str) -> bool {\n    serde_json::from_str::<serde_json::Value>(raw)\n        .ok()\n        .map(|v| v.get(\"result\").is_some() || v.get(\"error\").is_some())\n        .unwrap_or(false)\n}","tryCatchPattern":"match ext_call::<WorktreeInfo>(tx, \"worktree/show\", &params).await {\n    Ok(info) => use(info),\n    Err(e) if e.to_string().starts_with(\"response parse error\") => {\n        eprintln!(\"agent reply did not match expected schema: {e:#}\");\n        eprintln!(\"check CLI/agent version compatibility\");\n    }\n    Err(e) => return Err(e),\n}","preventionTips":["Pin CLI and agent to compatible ACP extension schema versions.","Make new agent response fields optional with #[serde(default)] to tolerate drift.","Log raw responses in debug mode to diagnose schema mismatches quickly.","Add deserialization round-trip tests against recorded agent responses."],"tags":["rust","serde","json","acp","protocol","deserialization"],"backgroundTag":"response-deserialization-failed","analyzedSha":"bc7f02eddd3d84085849dc19ed216f11c23b0571","analyzedAt":"2026-08-31T04:59:42.031Z","schemaVersion":2},"datasetVersion":"2026-08-31T09:17:48.483Z"}