diff --git a/src/cli.ts b/src/cli.ts
index a7a1f3783..c121f15f6 100644
--- a/src/cli.ts
+++ b/src/cli.ts
@@ -167,6 +167,7 @@ import resourceToolBlockerExtension from "./resources/tool-blocker.js"
 import { runSetupWizard } from "./setup-wizard.js"
 import { setAvailableModels } from "./startup-context.js"
 import { probeTerminalBackground } from "./terminal-bg-probe.js"
+import { installCollisionDiagnosticsPatch } from "./upstream-collision-diagnostics-patch.js"
 import { installInlineCompactPatch } from "./upstream-inline-compact-patch.js"
 import { installCompactionRecoveryPatch, installInfrastructureRetryPatch } from "./upstream-retry-patch.js"
 import {
@@ -187,6 +188,9 @@ installPiNativeCompatibilityShim()
 // InteractiveMode instance is constructed.
 applyInteractiveErrorSurfacePatch()
 applyInteractiveModelSessionPatch()
+// Hide non-actionable resource collisions from the startup report unless the
+// user asked for a verbose startup before the first loader update emits them.
+installCollisionDiagnosticsPatch()
 
 function getSubcommand(args: string[]): string {
 	if (args.includes("--version") || args.includes("-v")) return "version"
diff --git a/src/upstream-collision-diagnostics-patch.test.ts b/src/upstream-collision-diagnostics-patch.test.ts
new file mode 100644
index 000000000..0998fd7be
--- /dev/null
+++ b/src/upstream-collision-diagnostics-patch.test.ts
@@ -0,0 +1,132 @@
+import { DefaultResourceLoader, type ResourceDiagnostic } from "@earendil-works/pi-coding-agent"
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest"
+import { installCollisionDiagnosticsPatch } from "./upstream-collision-diagnostics-patch.js"
+
+const { getParsedCliArgs } = vi.hoisted(() => ({ getParsedCliArgs: vi.fn() }))
+vi.mock("./cli-args.js", () => ({ getParsedCliArgs }))
+
+const DIAGNOSTIC_SINKS = [
+	["updateSkillsFromPaths", "skillDiagnostics"],
+	["updatePromptsFromPaths", "promptDiagnostics"],
+	["updateThemesFromPaths", "themeDiagnostics"],
+] as const
+
+const collision: ResourceDiagnostic = {
+	type: "collision",
+	message: 'skill "duplicated" collides',
+	collision: {
+		resourceType: "skill",
+		name: "duplicated",
+		winnerPath: "/winner/SKILL.md",
+		loserPath: "/loser/SKILL.md",
+	},
+}
+const warning: ResourceDiagnostic = {
+	type: "warning",
+	message: "description exceeds 1024 characters (1273)",
+	path: "/tmp/skill/SKILL.md",
+}
+const error: ResourceDiagnostic = {
+	type: "error",
+	message: "resource failed to load",
+	path: "/tmp/broken/SKILL.md",
+}
+
+// biome-ignore lint/suspicious/noExplicitAny: private upstream prototype adapter
+const prototype = DefaultResourceLoader.prototype as any
+const originalMethods = new Map(DIAGNOSTIC_SINKS.map(([method]) => [method, prototype[method]]))
+
+let quietStartup = true
+function setVerbose(verbose: boolean): void {
+	getParsedCliArgs.mockReturnValue({ options: { verbose }, positionals: [] })
+}
+
+function resetPrototype(): void {
+	for (const [method] of DIAGNOSTIC_SINKS) {
+		prototype[method] = originalMethods.get(method)
+	}
+	prototype.__kimchiCollisionDiagnosticsPatchApplied = false
+}
+
+function runPatchOverStub(
+	method: string,
+	field: string,
+	diagnostics: ResourceDiagnostic[],
+	returnValue: unknown = undefined,
+): { returned: unknown; diagnostics: unknown } {
+	prototype[method] = function stubInner(this: Record<string, unknown>) {
+		this[field] = diagnostics
+		return returnValue
+	}
+	prototype.__kimchiCollisionDiagnosticsPatchApplied = false
+	installCollisionDiagnosticsPatch()
+
+	const instance: Record<string, unknown> = {
+		settingsManager: { getQuietStartup: () => quietStartup },
+	}
+	const returned = prototype[method].call(instance, [], new Map())
+	return { returned, diagnostics: instance[field] }
+}
+
+describe("installCollisionDiagnosticsPatch", () => {
+	beforeEach(() => {
+		setVerbose(false)
+		quietStartup = true
+		resetPrototype()
+		installCollisionDiagnosticsPatch()
+	})
+
+	afterEach(() => {
+		resetPrototype()
+		vi.restoreAllMocks()
+	})
+
+	it("targets existing synchronous upstream methods", () => {
+		for (const [method] of DIAGNOSTIC_SINKS) {
+			const original = originalMethods.get(method)
+			expect(typeof original, `${method} must exist upstream`).toBe("function")
+			expect(original.constructor.name, `${method} must remain synchronous`).not.toBe("AsyncFunction")
+		}
+	})
+
+	it("is idempotent so repeated bootstrap does not stack wrappers", () => {
+		const wrapped = prototype.updateSkillsFromPaths
+		installCollisionDiagnosticsPatch()
+		expect(prototype.updateSkillsFromPaths).toBe(wrapped)
+	})
+
+	it("drops only collision diagnostics on quiet startup and preserves return values", () => {
+		const returnValue = { skills: [], diagnostics: [] }
+		const { returned, diagnostics } = runPatchOverStub(
+			"updateSkillsFromPaths",
+			"skillDiagnostics",
+			[warning, collision, error],
+			returnValue,
+		)
+
+		expect(returned).toBe(returnValue)
+		expect(diagnostics).toEqual([warning, error])
+	})
+
+	it("keeps collision diagnostics and order when startup is verbose", () => {
+		setVerbose(true)
+		const input = [collision, warning, error]
+		const { diagnostics } = runPatchOverStub("updateSkillsFromPaths", "skillDiagnostics", input)
+
+		expect(diagnostics).toEqual(input)
+		expect(diagnostics).not.toBe(input)
+	})
+
+	it("keeps collision diagnostics when quietStartup is disabled in settings", () => {
+		quietStartup = false
+		const input = [collision, warning]
+		const { diagnostics } = runPatchOverStub("updateSkillsFromPaths", "skillDiagnostics", input)
+
+		expect(diagnostics).toEqual(input)
+	})
+
+	it.each(DIAGNOSTIC_SINKS)("filters %s into %s", (method, field) => {
+		const { diagnostics } = runPatchOverStub(method, field, [collision, warning])
+		expect(diagnostics).toEqual([warning])
+	})
+})
diff --git a/src/upstream-collision-diagnostics-patch.ts b/src/upstream-collision-diagnostics-patch.ts
new file mode 100644
index 000000000..a7fef5433
--- /dev/null
+++ b/src/upstream-collision-diagnostics-patch.ts
@@ -0,0 +1,77 @@
+import { DefaultResourceLoader, type ResourceDiagnostic } from "@earendil-works/pi-coding-agent"
+import { getParsedCliArgs } from "./cli-args.js"
+
+/**
+ * Startup diagnostics come in two flavours. A `collision` says two resources
+ * shared a name and precedence already picked a winner — a valid resource
+ * loaded, so there is nothing for the user to do. Everything else reports a
+ * resource that is actually broken, e.g. a skill whose description exceeds the
+ * 1024-character limit.
+ *
+ * Pi renders both unconditionally at startup (its `showDiagnosticsWhenQuiet`
+ * bypasses the `quietStartup` setting), which buries the actionable reports
+ * under collision noise. We drop only the collisions, and only when startup
+ * is actually quiet: the `quietStartup` setting is on and the user has not
+ * forced a verbose startup with `--verbose`.
+ *
+ * Because the filter mutates the stored diagnostics (there is no render-time
+ * hook — see below), keeping this gate in sync with Pi's render condition
+ * matters: users who disabled `quietStartup` opted into the full report and
+ * must keep their collision diagnostics.
+ */
+function filterCollisionDiagnostics(
+	diagnostics: readonly ResourceDiagnostic[],
+	options: { verbose: boolean; quietStartup: boolean },
+): ResourceDiagnostic[] {
+	if (options.verbose || !options.quietStartup) return [...diagnostics]
+	return diagnostics.filter((diagnostic) => diagnostic.type !== "collision")
+}
+
+/**
+ * The loader methods that resolve a resource kind, paired with the field each
+ * one writes its diagnostics to.
+ */
+const DIAGNOSTIC_SINKS = [
+	["updateSkillsFromPaths", "skillDiagnostics"],
+	["updatePromptsFromPaths", "promptDiagnostics"],
+	["updateThemesFromPaths", "themeDiagnostics"],
+] as const
+
+/**
+ * Drop non-actionable collision diagnostics from Pi's startup report when
+ * startup is quiet (`quietStartup` on, no `--verbose`).
+ *
+ * Pi exposes `skillsOverride` / `promptsOverride` / `themesOverride` for
+ * post-processing, but upstream `main()` builds the loader itself and accepts
+ * only `extensionFactories`, so the interactive path cannot thread them.
+ * Prototype accessors do not work because these hooks are class fields and
+ * every instance gets an own property that shadows the prototype.
+ *
+ * We therefore wrap the methods that publish diagnostics and filter what they
+ * stored. This runs after any caller-supplied `*Override`, so an explicit
+ * override (e.g. ACP's) still applies first.
+ *
+ * This adapter intentionally depends on private upstream names and assumes the
+ * update methods remain synchronous and keep assigning the fields listed
+ * above. The co-located tests guard both assumptions when Pi is upgraded.
+ */
+export function installCollisionDiagnosticsPatch(): void {
+	// biome-ignore lint/suspicious/noExplicitAny: private upstream prototype adapter
+	const prototype = DefaultResourceLoader.prototype as any
+	if (prototype.__kimchiCollisionDiagnosticsPatchApplied) return
+	prototype.__kimchiCollisionDiagnosticsPatchApplied = true
+
+	for (const [method, field] of DIAGNOSTIC_SINKS) {
+		const original = prototype[method]
+		if (typeof original !== "function") continue
+
+		// biome-ignore lint/suspicious/noExplicitAny: private upstream prototype adapter
+		prototype[method] = function patchedUpdate(this: any, ...args: unknown[]) {
+			const result = original.apply(this, args)
+			const verbose = getParsedCliArgs().options.verbose === true
+			const quietStartup = this.settingsManager.getQuietStartup()
+			this[field] = filterCollisionDiagnostics(this[field] ?? [], { verbose, quietStartup })
+			return result
+		}
+	}
+}