diff --git a/.changeset/merry-foxes-climb.md b/.changeset/merry-foxes-climb.md
new file mode 100644
index 000000000..e21ee9950
--- /dev/null
+++ b/.changeset/merry-foxes-climb.md
@@ -0,0 +1,5 @@
+---
+type: Fixed
+pr: 2997
+---
+SDK config-set/config-get and init responses no longer echo plaintext API keys. New sdk/src/query/secrets.ts ports SECRET_CONFIG_KEYS masking from CJS; init bundles only mask string values to preserve the boolean availability-flag contract. See #2997.
diff --git a/.changeset/plucky-moles-roam.md b/.changeset/plucky-moles-roam.md
new file mode 100644
index 000000000..e21ee9950
--- /dev/null
+++ b/.changeset/plucky-moles-roam.md
@@ -0,0 +1,5 @@
+---
+type: Fixed
+pr: 2997
+---
+SDK config-set/config-get and init responses no longer echo plaintext API keys. New sdk/src/query/secrets.ts ports SECRET_CONFIG_KEYS masking from CJS; init bundles only mask string values to preserve the boolean availability-flag contract. See #2997.
diff --git a/get-shit-done/bin/lib/init.cjs b/get-shit-done/bin/lib/init.cjs
index 1e2654729..3eaa42374 100644
--- a/get-shit-done/bin/lib/init.cjs
+++ b/get-shit-done/bin/lib/init.cjs
@@ -7,6 +7,7 @@ const path = require('path');
 const { execSync } = require('child_process');
 const { loadConfig, resolveModelInternal, findPhaseInternal, getRoadmapPhaseInternal, pathExistsInternal, generateSlugInternal, getMilestoneInfo, getMilestonePhaseFilter, stripShippedMilestones, extractCurrentMilestone, normalizePhaseName, toPosixPath, output, error, checkAgentsInstalled, phaseTokenMatches } = require('./core.cjs');
 const { planningPaths, planningDir, planningRoot } = require('./planning-workspace.cjs');
+const { maskIfSecret } = require('./secrets.cjs');
 
 // Accept all bold/colon variants of the Requirements header (#2769):
 // **Requirements:** / **Requirements**: / **Requirements** : render the
@@ -725,9 +726,13 @@ function cmdInitPhaseOp(cwd, phase, raw) {
   const result = {
     // Config
     commit_docs: config.commit_docs,
-    brave_search: config.brave_search,
-    firecrawl: config.firecrawl,
-    exa_search: config.exa_search,
+    // #2997: secret config keys may be either booleans (availability flags) or
+    // string API keys (when user did `gsd-tools config-set brave_search XXX`).
+    // Pass booleans through; mask string values so the init bundle never echoes
+    // plaintext credentials. SDK init.ts mirrors this masking.
+    brave_search: typeof config.brave_search === 'string' ? maskIfSecret('brave_search', config.brave_search) : config.brave_search,
+    firecrawl: typeof config.firecrawl === 'string' ? maskIfSecret('firecrawl', config.firecrawl) : config.firecrawl,
+    exa_search: typeof config.exa_search === 'string' ? maskIfSecret('exa_search', config.exa_search) : config.exa_search,
 
     // Phase info
     phase_found: !!phaseInfo,
diff --git a/sdk/src/query/config-mutation.test.ts b/sdk/src/query/config-mutation.test.ts
index 44f544b72..e95d9b867 100644
--- a/sdk/src/query/config-mutation.test.ts
+++ b/sdk/src/query/config-mutation.test.ts
@@ -492,3 +492,54 @@ describe('configEnsureSection', () => {
     expect(raw.workflow).toEqual({ research: true });
   });
 });
+
+// ─── #2997: Secret masking in configSet response ────────────────────────────
+
+describe('configSet secret masking (#2997)', () => {
+  it('masks the response value for SECRET_CONFIG_KEYS, leaving on-disk plaintext intact', async () => {
+    const { configSet } = await import('./config-mutation.js');
+    const apiKey = 'BSA-1234567890abcdef';
+    const result = await configSet(['brave_search', apiKey], tmpDir);
+    const data = result.data as { value: string };
+    // Response is masked
+    expect(data.value).toBe('****cdef');
+    expect(data.value).not.toContain(apiKey);
+    // On-disk plaintext is intact (the key is usable)
+    const raw = JSON.parse(await readFile(join(tmpDir, '.planning', 'config.json'), 'utf-8'));
+    expect(raw.brave_search).toBe(apiKey);
+  });
+
+  it('masks previousValue when overwriting an existing secret', async () => {
+    const { configSet } = await import('./config-mutation.js');
+    await writeFile(
+      join(tmpDir, '.planning', 'config.json'),
+      JSON.stringify({ brave_search: 'OLD-KEY-1234567890' }),
+    );
+    const result = await configSet(['brave_search', 'NEW-KEY-abcdef9999'], tmpDir);
+    const data = result.data as { value: string; previousValue: string };
+    expect(data.value).toBe('****9999');
+    expect(data.previousValue).toBe('****7890');
+    expect(data.previousValue).not.toContain('OLD-KEY');
+  });
+
+  it('does NOT mask non-secret keys', async () => {
+    const { configSet } = await import('./config-mutation.js');
+    const result = await configSet(['model_profile', 'quality'], tmpDir);
+    const data = result.data as { value: string };
+    expect(data.value).toBe('quality');
+  });
+
+  it('renders short secret values as **** (no tail leak)', async () => {
+    const { configSet } = await import('./config-mutation.js');
+    const result = await configSet(['firecrawl', 'short'], tmpDir);
+    const data = result.data as { value: string };
+    expect(data.value).toBe('****');
+  });
+
+  it('renders unset/empty as (unset) in the response', async () => {
+    const { configSet } = await import('./config-mutation.js');
+    const result = await configSet(['exa_search', ''], tmpDir);
+    const data = result.data as { value: string };
+    expect(data.value).toBe('(unset)');
+  });
+});
diff --git a/sdk/src/query/config-mutation.ts b/sdk/src/query/config-mutation.ts
index 0c3aea73d..4ac28f7df 100644
--- a/sdk/src/query/config-mutation.ts
+++ b/sdk/src/query/config-mutation.ts
@@ -26,6 +26,7 @@ import { VALID_PROFILES, getAgentToModelMapForProfile } from './config-query.js'
 import { VALID_CONFIG_KEYS, DYNAMIC_KEY_PATTERNS } from './config-schema.js';
 import { planningPaths } from './helpers.js';
 import { acquireStateLock, releaseStateLock } from './state-mutation.js';
+import { maskIfSecret } from './secrets.js';
 import type { QueryHandler } from './utils.js';
 
 /**
@@ -233,14 +234,17 @@ export const configSet: QueryHandler = async (args, projectDir, workstream) => {
     await releaseStateLock(lockPath);
   }
 
-  // Match CJS JSON: `JSON.stringify` omits keys whose value is `undefined`
+  // Mask plaintext for keys in SECRET_CONFIG_KEYS to match CJS behavior at
+  // config.cjs:362-370 — without this, `gsd-sdk query config-set brave_search XXX`
+  // would echo the plaintext credential into machine-readable output. (#2997)
+  // The on-disk value is intentionally NOT masked — only the response.
   const data: Record<string, unknown> = {
     updated: true,
     key: keyPath,
-    value: parsedValue,
+    value: maskIfSecret(keyPath, parsedValue),
   };
   if (previousValue !== undefined) {
-    data.previousValue = previousValue;
+    data.previousValue = maskIfSecret(keyPath, previousValue);
   }
   return { data };
 };
diff --git a/sdk/src/query/config-query.test.ts b/sdk/src/query/config-query.test.ts
index 634363305..dca26ed61 100644
--- a/sdk/src/query/config-query.test.ts
+++ b/sdk/src/query/config-query.test.ts
@@ -219,3 +219,50 @@ describe('VALID_PROFILES', () => {
     expect(VALID_PROFILES).toEqual(['quality', 'balanced', 'budget', 'adaptive']);
   });
 });
+
+// ─── #2997: Secret masking in configGet response ────────────────────────────
+
+describe('configGet secret masking (#2997)', () => {
+  it('masks the response data for SECRET_CONFIG_KEYS', async () => {
+    const { configGet } = await import('./config-query.js');
+    const apiKey = 'BSA-1234567890abcdef';
+    await writeFile(
+      join(tmpDir, '.planning', 'config.json'),
+      JSON.stringify({ brave_search: apiKey }),
+    );
+    const result = await configGet(['brave_search'], tmpDir);
+    expect(result.data).toBe('****cdef');
+    expect(result.data).not.toBe(apiKey);
+  });
+
+  it('does NOT mask non-secret keys', async () => {
+    const { configGet } = await import('./config-query.js');
+    await writeFile(
+      join(tmpDir, '.planning', 'config.json'),
+      JSON.stringify({ model_profile: 'quality' }),
+    );
+    const result = await configGet(['model_profile'], tmpDir);
+    expect(result.data).toBe('quality');
+  });
+
+  it('renders short secret values as **** (no tail leak)', async () => {
+    const { configGet } = await import('./config-query.js');
+    await writeFile(
+      join(tmpDir, '.planning', 'config.json'),
+      JSON.stringify({ firecrawl: 'abc' }),
+    );
+    const result = await configGet(['firecrawl'], tmpDir);
+    expect(result.data).toBe('****');
+  });
+
+  it('does not mask the user-supplied --default value (it is the user\'s own input, not a stored secret)', async () => {
+    const { configGet } = await import('./config-query.js');
+    await writeFile(
+      join(tmpDir, '.planning', 'config.json'),
+      JSON.stringify({ model_profile: 'balanced' }),
+    );
+    const result = await configGet(['brave_search', '--default', 'placeholder'], tmpDir);
+    // Default flows through unchanged: the user typed it, the SDK echoed it.
+    expect(result.data).toBe('placeholder');
+  });
+});
diff --git a/sdk/src/query/config-query.ts b/sdk/src/query/config-query.ts
index 4c18bcd36..1d3e54725 100644
--- a/sdk/src/query/config-query.ts
+++ b/sdk/src/query/config-query.ts
@@ -20,6 +20,7 @@ import { readFile } from 'node:fs/promises';
 import { GSDError, ErrorClassification } from '../errors.js';
 import { loadConfig } from '../config.js';
 import { planningPaths } from './helpers.js';
+import { maskIfSecret } from './secrets.js';
 import type { QueryHandler } from './utils.js';
 
 // ─── MODEL_PROFILES ─────────────────────────────────────────────────────────
@@ -129,7 +130,10 @@ export const configGet: QueryHandler = async (args, projectDir, workstream) => {
     throw new GSDError(`Key not found: ${keyPath}`, ErrorClassification.Execution);
   }
 
-  return { data: current };
+  // Mask plaintext for keys in SECRET_CONFIG_KEYS to match CJS behavior at
+  // config.cjs:440-441 — without this, `gsd-sdk query config-get brave_search`
+  // would echo the plaintext credential into machine-readable output. (#2997)
+  return { data: maskIfSecret(keyPath, current) };
 };
 
 // ─── configPath ─────────────────────────────────────────────────────────────
diff --git a/sdk/src/query/init.ts b/sdk/src/query/init.ts
index 0dacc300b..8f1488719 100644
--- a/sdk/src/query/init.ts
+++ b/sdk/src/query/init.ts
@@ -25,6 +25,7 @@ import { homedir } from 'node:os';
 
 import { loadConfig, type GSDConfig } from '../config.js';
 import { resolveModel, MODEL_PROFILES } from './config-query.js';
+import { maskIfSecret } from './secrets.js';
 import { findPhase } from './phase.js';
 import { roadmapGetPhase, getMilestoneInfo, extractCurrentMilestone, extractPhasesFromSection } from './roadmap.js';
 import { planningPaths, normalizePhaseName, toPosixPath, resolveAgentsDir, detectRuntime } from './helpers.js';
@@ -670,9 +671,14 @@ export const initPhaseOp: QueryHandler = async (args, projectDir, workstream) =>
 
   const result: Record<string, unknown> = {
     commit_docs: config.commit_docs,
-    brave_search: config.brave_search,
-    firecrawl: config.firecrawl,
-    exa_search: config.exa_search,
+    // #2997: secret config keys (brave_search, firecrawl, exa_search) may be
+    // either boolean availability flags OR string API keys depending on how the
+    // user configured them. Pass booleans through; mask string values so the
+    // init bundle never echoes plaintext credentials. Mirrors the masking added
+    // to config-get/config-set in the same fix.
+    brave_search: typeof config.brave_search === 'string' ? maskIfSecret('brave_search', config.brave_search) : config.brave_search,
+    firecrawl: typeof config.firecrawl === 'string' ? maskIfSecret('firecrawl', config.firecrawl) : config.firecrawl,
+    exa_search: typeof config.exa_search === 'string' ? maskIfSecret('exa_search', config.exa_search) : config.exa_search,
     phase_found: phaseFound,
     phase_dir: (phaseInfo?.directory as string) ?? null,
     phase_number: phaseNumber,
diff --git a/sdk/src/query/secrets.test.ts b/sdk/src/query/secrets.test.ts
new file mode 100644
index 000000000..d1ec55487
--- /dev/null
+++ b/sdk/src/query/secrets.test.ts
@@ -0,0 +1,66 @@
+import { describe, it } from 'vitest';
+import assert from 'node:assert/strict';
+import { SECRET_CONFIG_KEYS, isSecretKey, maskSecret, maskIfSecret } from './secrets.js';
+// Parity check against the CJS module.
+import secretsCjs from '../../../get-shit-done/bin/lib/secrets.cjs';
+
+describe('Bug #2997: SDK secrets module', () => {
+  it('SECRET_CONFIG_KEYS exposes the documented set (locked)', () => {
+    assert.deepEqual([...SECRET_CONFIG_KEYS].sort(), ['brave_search', 'exa_search', 'firecrawl']);
+  });
+
+  it('isSecretKey returns true for each registered secret', () => {
+    for (const k of SECRET_CONFIG_KEYS) {
+      assert.equal(isSecretKey(k), true, `${k} should be a secret`);
+    }
+  });
+
+  it('isSecretKey returns false for unrelated keys', () => {
+    for (const k of ['model_profile', 'commit_docs', 'workflow.plan_bounce', 'unknown_key']) {
+      assert.equal(isSecretKey(k), false);
+    }
+  });
+
+  it('maskSecret renders the convention ****<last-4> for ≥8-char strings', () => {
+    assert.equal(maskSecret('BSA-secret-key-abcd1234'), '****1234');
+    assert.equal(maskSecret('12345678'), '****5678');
+  });
+
+  it('maskSecret renders **** with no tail for <8-char strings', () => {
+    assert.equal(maskSecret('short'), '****');
+    assert.equal(maskSecret('abc'), '****');
+    assert.equal(maskSecret('1234567'), '****');
+  });
+
+  it('maskSecret renders (unset) for null/undefined/empty', () => {
+    assert.equal(maskSecret(null), '(unset)');
+    assert.equal(maskSecret(undefined), '(unset)');
+    assert.equal(maskSecret(''), '(unset)');
+  });
+
+  it('maskIfSecret passes non-secret values through unchanged', () => {
+    assert.equal(maskIfSecret('model_profile', 'quality'), 'quality');
+    assert.equal(maskIfSecret('commit_docs', true), true);
+  });
+
+  it('maskIfSecret masks secret values', () => {
+    assert.equal(maskIfSecret('brave_search', 'BSA-1234567890'), '****7890');
+    assert.equal(maskIfSecret('firecrawl', null), '(unset)');
+  });
+
+  // Parity with the CJS module — single source of truth via test enforcement,
+  // not import. Ensures SDK and CJS can never drift on the masking rule.
+  describe('CJS parity (#2997)', () => {
+    it('SECRET_CONFIG_KEYS matches the CJS set exactly', () => {
+      const cjsKeys = [...secretsCjs.SECRET_CONFIG_KEYS].sort();
+      const tsKeys = [...SECRET_CONFIG_KEYS].sort();
+      assert.deepEqual(tsKeys, cjsKeys);
+    });
+
+    for (const sample of ['', 'a', 'abc', '12345678', 'BSA-1234567890', null, undefined]) {
+      it(`maskSecret(${JSON.stringify(sample)}) matches CJS output`, () => {
+        assert.equal(maskSecret(sample), secretsCjs.maskSecret(sample));
+      });
+    }
+  });
+});
diff --git a/sdk/src/query/secrets.ts b/sdk/src/query/secrets.ts
new file mode 100644
index 000000000..9a5e2d758
--- /dev/null
+++ b/sdk/src/query/secrets.ts
@@ -0,0 +1,43 @@
+/**
+ * Secrets handling — TypeScript mirror of `get-shit-done/bin/lib/secrets.cjs`.
+ *
+ * Keys considered sensitive (`SECRET_CONFIG_KEYS`) are masked in any
+ * machine-readable response from `config-set` / `config-get` so plaintext
+ * credentials don't end up in workflow output, session transcripts, or
+ * shell histories. The on-disk value is unchanged; only the response is masked.
+ *
+ * Behavior must match `secrets.cjs` exactly. A parity test asserts the
+ * two modules expose the same set of secret keys and produce identical
+ * masked output for representative inputs.
+ *
+ * Tracked in #2997 (security: SDK port lost masking behavior).
+ */
+
+export const SECRET_CONFIG_KEYS: ReadonlySet<string> = new Set([
+  'brave_search',
+  'firecrawl',
+  'exa_search',
+]);
+
+export function isSecretKey(keyPath: string): boolean {
+  return SECRET_CONFIG_KEYS.has(keyPath);
+}
+
+/**
+ * Convention: ≥8 chars → `****<last-4>`; <8 chars → `****`; null/empty/undefined → `(unset)`.
+ * Identical to `secrets.cjs` `maskSecret`.
+ */
+export function maskSecret(value: unknown): string {
+  if (value === null || value === undefined || value === '') return '(unset)';
+  const s = String(value);
+  if (s.length < 8) return '****';
+  return '****' + s.slice(-4);
+}
+
+/**
+ * Helper: returns the value masked if `keyPath` is a secret, else the value
+ * unchanged. Use at response-construction boundaries in query handlers.
+ */
+export function maskIfSecret<T>(keyPath: string, value: T): T | string {
+  return isSecretKey(keyPath) ? maskSecret(value) : value;
+}