From ac538427013b397cb23252db36892c92ee0f4208 Mon Sep 17 00:00:00 2001
From: Rohit Ghumare <ghumare64@gmail.com>
Date: Wed, 20 May 2026 16:47:30 +0100
Subject: [PATCH] fix(observe): auto-create session row + surface session/start
 HTTP errors
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Closes a silent data-loss path: when an agent hook calls
POST /agentmemory/observe before (or instead of) a successful
POST /agentmemory/session/start, observations were written to
KV.observations(sessionId) but KV.sessions never got the parent row.
GET /agentmemory/sessions then returned an empty list even though the
underlying observation files were on disk.

Two complementary changes:

1. Server-side (src/functions/observe.ts) — when observe lands and the
   session row is missing, insert it inline using the project / cwd /
   timestamp / first prompt already present on the payload. session/start
   remains the fast path (it also returns the inject-context block) but
   is no longer load-bearing for durability.

2. Hook-side (src/hooks/session-start.ts) — explicit stderr write when
   session/start returns a non-2xx status, on both the fire-and-forget
   and inject-context paths. Network / timeout errors stay quiet (common
   on cold-start); HTTP errors surface so wiring problems (wrong URL,
   auth, etc.) become visible to the user. The compiled
   plugin/scripts/session-start.mjs is regenerated by tsdown.

Tests (1081) + build pass.
---
 plugin/scripts/session-start.mjs |  4 +++-
 src/functions/observe.ts         | 22 ++++++++++++++++++++++
 src/hooks/session-start.ts       | 24 +++++++++++++++++++++---
 3 files changed, 46 insertions(+), 4 deletions(-)

diff --git a/plugin/scripts/session-start.mjs b/plugin/scripts/session-start.mjs
index 9e573e24..12e6d91e 100755
--- a/plugin/scripts/session-start.mjs
+++ b/plugin/scripts/session-start.mjs
@@ -41,6 +41,8 @@ async function main() {
 		fetch(url, {
 			...init,
 			signal: AbortSignal.timeout(REGISTER_TIMEOUT_MS)
+		}).then((res) => {
+			if (!res.ok) process.stderr.write(`[agentmemory] session/start returned ${res.status} for ${sessionId}\n`);
 		}).catch(() => {});
 		return;
 	}
@@ -52,7 +54,7 @@ async function main() {
 		if (res.ok) {
 			const result = await res.json();
 			if (result.context) process.stdout.write(result.context);
-		}
+		} else process.stderr.write(`[agentmemory] session/start returned ${res.status} for ${sessionId}\n`);
 	} catch {}
 }
 main();
diff --git a/src/functions/observe.ts b/src/functions/observe.ts
index 57e2f7df..092de67b 100644
--- a/src/functions/observe.ts
+++ b/src/functions/observe.ts
@@ -214,6 +214,28 @@ export function registerObserveFunction(
             }
           }
           await kv.update(KV.sessions, payload.sessionId, updates);
+        } else {
+          // Auto-create the session row when an observation arrives before
+          // (or instead of) a successful session/start call. The hook
+          // scripts call session/start as fire-and-forget; on transient
+          // server unavailability that POST is silently dropped, leaving
+          // observations orphaned from GET /agentmemory/sessions even
+          // though they're present on disk. Re-creating here closes the
+          // data-loss hole permanently; session/start remains the fast
+          // path (it also returns the injected context).
+          const firstPrompt =
+            typeof raw.userPrompt === "string"
+              ? raw.userPrompt.replace(/\s+/g, " ").trim().slice(0, 200)
+              : undefined;
+          await kv.set(KV.sessions, payload.sessionId, {
+            id: payload.sessionId,
+            project: payload.project,
+            cwd: payload.cwd,
+            startedAt: payload.timestamp,
+            status: "active",
+            observationCount: 1,
+            ...(firstPrompt ? { firstPrompt } : {}),
+          });
         }
 
         // Per-observation LLM compression is opt-in as of 0.8.8 (#138).
diff --git a/src/hooks/session-start.ts b/src/hooks/session-start.ts
index a6cefe41..bd7c58e6 100644
--- a/src/hooks/session-start.ts
+++ b/src/hooks/session-start.ts
@@ -62,11 +62,24 @@ async function main() {
   if (!INJECT_CONTEXT) {
     // Pure telemetry path: caller never reads the response, so don't
     // block on it. AbortSignal.timeout caps the wait the event loop
-    // gives the pending socket before exit.
+    // gives the pending socket before exit. Server-side observe now
+    // auto-creates a session row when one is missing (#522), so a
+    // dropped POST here is a missed context-inject, not data loss.
     fetch(url, {
       ...init,
       signal: AbortSignal.timeout(REGISTER_TIMEOUT_MS),
-    }).catch(() => {});
+    })
+      .then((res) => {
+        // Surface HTTP errors so wiring problems (wrong URL, auth)
+        // don't stay invisible. Network/timeout errors fall through
+        // to .catch() and stay quiet — those are common on cold-start.
+        if (!res.ok) {
+          process.stderr.write(
+            `[agentmemory] session/start returned ${res.status} for ${sessionId}\n`,
+          );
+        }
+      })
+      .catch(() => {});
     return;
   }
 
@@ -80,9 +93,14 @@ async function main() {
       if (result.context) {
         process.stdout.write(result.context);
       }
+    } else {
+      process.stderr.write(
+        `[agentmemory] session/start returned ${res.status} for ${sessionId}\n`,
+      );
     }
   } catch {
-    // silently fail -- don't block Claude Code startup
+    // network/timeout — don't block Claude Code startup; observe-side
+    // will still pick up the session via auto-upsert (#522).
   }
 }