diff --git a/src/resources/extensions/gsd/bootstrap/system-context.ts b/src/resources/extensions/gsd/bootstrap/system-context.ts
index ef51c9ff0..c82217449 100644
--- a/src/resources/extensions/gsd/bootstrap/system-context.ts
+++ b/src/resources/extensions/gsd/bootstrap/system-context.ts
@@ -264,6 +264,13 @@ function buildWorktreeContextBlock(): string {
   return "";
 }
 
+/**
+ * Low-entropy resume intent patterns — short phrases a user types to
+ * continue work after a pause, rate limit, or context reset (#3615).
+ * Tested against the trimmed, lowercased prompt with trailing punctuation stripped.
+ */
+const RESUME_INTENT_PATTERNS = /^(continue|resume|ok|go|go ahead|proceed|keep going|carry on|next|yes|yeah|yep|sure|do it|let's go|pick up where you left off)$/;
+
 async function buildGuidedExecuteContextInjection(prompt: string, basePath: string): Promise<string | null> {
   const executeMatch = prompt.match(/Execute the next task:\s+(T\d+)\s+\("([^"]+)"\)\s+in slice\s+(S\d+)\s+of milestone\s+(M\d+(?:-[a-z0-9]{6})?)/i);
   if (executeMatch) {
@@ -280,6 +287,27 @@ async function buildGuidedExecuteContextInjection(prompt: string, basePath: stri
     }
   }
 
+  // Fallback: low-entropy resume prompt (e.g., "continue", "ok", "go ahead")
+  // during an active executing task — inject task context so the agent
+  // doesn't rebuild from scratch (#3615).
+  // Intent-gated: only fire for short, resume-like prompts to avoid hijacking
+  // control/help/diagnostic prompts with unrelated execution context.
+  // Phase-gated: only fire during "executing" to avoid misrouting during
+  // replanning, gate evaluation, or other non-execution phases.
+  const trimmed = prompt.trim().toLowerCase().replace(/[.!?,]+$/g, "");
+  if (RESUME_INTENT_PATTERNS.test(trimmed)) {
+    const state = await deriveState(basePath);
+    if (state.phase === "executing" && state.activeTask && state.activeMilestone && state.activeSlice) {
+      return buildTaskExecutionContextInjection(
+        basePath,
+        state.activeMilestone.id,
+        state.activeSlice.id,
+        state.activeTask.id,
+        state.activeTask.title,
+      );
+    }
+  }
+
   return null;
 }
 
diff --git a/src/resources/extensions/gsd/tests/unstructured-continue-context-injection.test.ts b/src/resources/extensions/gsd/tests/unstructured-continue-context-injection.test.ts
new file mode 100644
index 000000000..c784bc421
--- /dev/null
+++ b/src/resources/extensions/gsd/tests/unstructured-continue-context-injection.test.ts
@@ -0,0 +1,163 @@
+// GSD-2 — Regression test for #3615: unstructured "continue" must inject task context
+// Copyright (c) 2026 Jeremy McSpadden <jeremy@fluxlabs.net>
+
+/**
+ * Bug #3615: When a user types "continue" (or any bare text) to resume
+ * an in-progress session, buildGuidedExecuteContextInjection() only
+ * matched two hardcoded regex patterns (auto-dispatch and guided-resume).
+ * The function returned null for any other input, so no task context was
+ * injected — causing the agent to rebuild everything from scratch and
+ * burn ~86k tokens.
+ *
+ * This test verifies:
+ *   1. Structural: the fallback exists with phase + intent guards
+ *   2. Behavioral: RESUME_INTENT_PATTERNS matches expected prompts and
+ *      rejects non-resume prompts (control, help, diagnostic, etc.)
+ */
+
+import { describe, test } from "node:test";
+import assert from "node:assert/strict";
+import { readFileSync } from "node:fs";
+import { join, dirname } from "node:path";
+import { fileURLToPath } from "node:url";
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+const systemContextSource = readFileSync(
+  join(__dirname, "..", "bootstrap", "system-context.ts"),
+  "utf-8",
+);
+
+// ── Structural tests ────────────────────────────────────────────────
+
+describe("#3615 — structural: fallback exists with correct guards", () => {
+  const fnStart = systemContextSource.indexOf("async function buildGuidedExecuteContextInjection(");
+  assert.ok(fnStart >= 0, "should find buildGuidedExecuteContextInjection");
+  const fnEnd = systemContextSource.indexOf("\nasync function ", fnStart + 1);
+  const fnBody = fnEnd >= 0
+    ? systemContextSource.slice(fnStart, fnEnd)
+    : systemContextSource.slice(fnStart);
+
+  test("has a deriveState fallback after the two regex branches", () => {
+    const deriveStateCalls = fnBody.match(/deriveState\(basePath\)/g);
+    assert.ok(
+      deriveStateCalls && deriveStateCalls.length >= 2,
+      `expected >=2 deriveState(basePath) calls, got ${deriveStateCalls?.length ?? 0}`,
+    );
+  });
+
+  test("fallback is phase-gated to executing only", () => {
+    const afterFallback = fnBody.indexOf("// Fallback:");
+    assert.ok(afterFallback >= 0, "should have a fallback comment");
+    const fallbackSection = fnBody.slice(afterFallback);
+    assert.ok(
+      fallbackSection.includes('state.phase === "executing"'),
+      'fallback must be gated on state.phase === "executing"',
+    );
+  });
+
+  test("fallback is intent-gated via RESUME_INTENT_PATTERNS", () => {
+    const afterFallback = fnBody.indexOf("// Fallback:");
+    const fallbackSection = fnBody.slice(afterFallback);
+    assert.ok(
+      fallbackSection.includes("RESUME_INTENT_PATTERNS"),
+      "fallback must check RESUME_INTENT_PATTERNS before deriveState",
+    );
+  });
+
+  test("fallback calls buildTaskExecutionContextInjection with derived state", () => {
+    const afterFallback = fnBody.indexOf("// Fallback:");
+    const fallbackSection = fnBody.slice(afterFallback);
+    assert.ok(
+      fallbackSection.includes("buildTaskExecutionContextInjection") &&
+      fallbackSection.includes("state.activeMilestone.id") &&
+      fallbackSection.includes("state.activeSlice.id") &&
+      fallbackSection.includes("state.activeTask.id"),
+      "fallback must call buildTaskExecutionContextInjection with state-derived IDs",
+    );
+  });
+
+  test("only one return null at the end", () => {
+    const returnNulls = fnBody.match(/return null;/g);
+    assert.ok(
+      returnNulls && returnNulls.length === 1,
+      `expected exactly 1 'return null' (at end after fallback), got ${returnNulls?.length ?? 0}`,
+    );
+  });
+});
+
+// ── Behavioral tests: RESUME_INTENT_PATTERNS ────────────────────────
+
+describe("#3615 — behavioral: RESUME_INTENT_PATTERNS matches resume prompts", () => {
+  // Extract the regex from source so the test stays in sync
+  const patternMatch = systemContextSource.match(/const RESUME_INTENT_PATTERNS\s*=\s*\/(.+)\/;/);
+  assert.ok(patternMatch, "should find RESUME_INTENT_PATTERNS definition");
+  const pattern = new RegExp(patternMatch[1]);
+
+  // Helper: normalize prompt the same way the production code does
+  const normalize = (s: string) => s.trim().toLowerCase().replace(/[.!?,]+$/g, "");
+
+  const shouldMatch = [
+    "continue",
+    "Continue",
+    "CONTINUE",
+    "continue.",
+    "continue!",
+    "resume",
+    "ok",
+    "OK",
+    "Ok!",
+    "go",
+    "go ahead",
+    "Go ahead.",
+    "proceed",
+    "keep going",
+    "carry on",
+    "next",
+    "yes",
+    "yeah",
+    "yep",
+    "sure",
+    "do it",
+    "let's go",
+    "pick up where you left off",
+    "  continue  ",  // whitespace padded
+  ];
+
+  const shouldNotMatch = [
+    "help",
+    "status",
+    "/gsd auto",
+    "/gsd stats",
+    "what's the plan?",
+    "show me the logs",
+    "abort",
+    "stop",
+    "cancel",
+    "replan this slice",
+    "I think we should change the approach",
+    "can you explain what you just did?",
+    "run the tests",
+    "check the build",
+    "Execute the next task: T01",
+    "what files were changed",
+    "",
+  ];
+
+  for (const prompt of shouldMatch) {
+    test(`matches resume prompt: "${prompt}"`, () => {
+      assert.ok(
+        pattern.test(normalize(prompt)),
+        `expected RESUME_INTENT_PATTERNS to match "${prompt}" (normalized: "${normalize(prompt)}")`,
+      );
+    });
+  }
+
+  for (const prompt of shouldNotMatch) {
+    test(`rejects non-resume prompt: "${prompt}"`, () => {
+      assert.ok(
+        !pattern.test(normalize(prompt)),
+        `expected RESUME_INTENT_PATTERNS to NOT match "${prompt}" (normalized: "${normalize(prompt)}")`,
+      );
+    });
+  }
+});