Substance is right. Walked the call site at 01_console.js:540–614:

• proxyDetails = core.getProxyDetails(value) is already computed unconditionally at line 540, so the proxyDetails ? proxyDetails[0] : value switch is free.
• For non-proxy objects, proxyDetails === null → inspectTarget = value — semantics unchanged.
• For actual Proxy objects, accessing target[nodeCustomInspectSymbol] bypasses the get trap entirely. A grammy-style proxy with get(_, p) => () => {} no longer fabricates a "custom inspect" function under our feet.
• FunctionPrototypeCall(maybeCustom, context, ...) still invokes with context = value (the proxy), so this inside a legitimate target-defined custom inspector is the proxy — matching Node.

This matches what Node's lib/internal/util/inspect.js does: peeks through proxies before consulting the inspect symbol. ✓

Test is well-targeted: a proxy with a tracking get trap; Deno.inspect(proxy); assert the inspect symbol was never accessed. Regression-tight to #33719.

One observation — non-blocking

The fix only redirects the third lookup branch (nodeCustomInspectSymbol). The branches above it still touch the proxy directly:

if (ReflectHas(value, customInspect) && typeof value[customInspect] === "function") {
  return String(value[customInspect](inspect, ctx));
} else if (ReflectHas(value, privateCustomInspect) && typeof value[privateCustomInspect] === "function") {
  return String(value[privateCustomInspect](inspect, ctx));
} else {
  // [the fixed branch]
}

For the grammy case specifically this is fine — those proxies don't override the has trap, so ReflectHas(value, customInspect) falls through to [[HasProperty]] on the underlying target and returns false, skipping the branch entirely. The fixed branch was the only one that actually fires.

But a more pathological proxy that does implement has to return true for everything would still trigger the get trap on value[customInspect] / value[privateCustomInspect]. If the philosophy is "Node unwraps proxies before consulting custom-inspect symbols, full stop," consider extending the same unwrap to the Deno-symbol branches:

const inspectTarget = proxyDetails ? proxyDetails[0] : value;
if (ReflectHas(inspectTarget, customInspect) && typeof inspectTarget[customInspect] === "function") {
  return String(value[customInspect](inspect, ctx));  // still call via `value` for `this` parity
}

Or document why Deno's symbols intentionally go through the proxy (e.g. allowing proxies to expose custom inspection without an underlying target object). Either way, worth a code comment so the asymmetry is intentional.

CI

1 fail (test integration (2/2) release linux-x86_64), 7 pending. The fail is the recurring sysroot/incremental-LTO setup step (exit code 2, 0 bytes copied, 10.0143 s, 0.0 kB/s — looks like a flaky artifact download), not a real test failure — the test step "Test (release)" never ran. Pending jobs (mostly macos-x86_64) should settle.

Holding to COMMENT until CI lands. Substance is clean; happy to flip to APPROVE once the macos shards finish and the integration job either succeeds on retry or is re-confirmed as the artifact-download flake.

LGTM at 77a32f2. The post-COMMENT delta extends the unwrap from just nodeCustomInspectSymbol to all three inspect symbols (Deno.customInspect, Deno.privateCustomInspect, nodejs.util.inspect.custom), which is the right scope. Verified at 01_console.js:548–614:

• inspectTarget = proxyDetails ? proxyDetails[0] : value — single hoisted unwrap reused for both branches' ReflectHas and property lookup. Non-proxy paths get inspectTarget === value, semantics unchanged.
• For Proxies: the has/get traps are bypassed for the lookup (which is where the grammy-proxy bug fires — a proxy returning () => {} for any prop would otherwise be detected as a custom-inspect function). The actual call still uses value[customInspect](inspect, ctx) to preserve this === value per Node's contract — that's intentional, and only fires when the underlying target has a real method.
• Test at console_test.ts:2680–2711 was correctly expanded: has trap added (since ReflectHas triggers has on a non-extended proxy), and the assertion now covers all three inspect symbols by matching the symbol names defined at 01_console.js:456,462,4026.
• CI: 134/136 success, 1 skip, 1 cla pending. No failures.