To His Eminence, the Patrician of Ankh‑Morpork, (Dec 20, 2025)¶

Sir,

As instructed, the activities of the Scarlet Semaphore continue under observation. Their remit remains experimentation: testing what happens when routing assumptions are questioned, signs are rearranged, and in some cases the Registry itself is quietly edited.

The Department of Silent Stability has complied with its instruction not to interfere. We have limited ourselves to observation, measurement, and analysis, with particular attention to what these exercises reveal about city‑wide stability and the resilience of our trust mechanisms.

I report the following.

The Red Lantern scenarios currently under execution unfold in a mechanically consistent manner. Given the same starting conditions, the same announcements are made, the same withdrawals occur, and the same telemetry is produced. From the perspective of the machinery, the exercises are predictable.

Where predictability becomes less clear is at the level that concerns Your Excellency most: interpretation and defence.

Several factors contribute to this.

First, the Scarlet Semaphore deliberately employs realistic timing and partial propagation. Announcements do not reach all quarters at once, nor do withdrawals occur cleanly or symmetrically. This reflects the city as it is, not as we might prefer it. The consequence is that defensive observers see effects that are locally consistent but globally uneven. Nothing here is random, yet it is not immediately obvious what should be expected without prior knowledge of the exercise’s intent.

Second, the scope of each exercise is implicit rather than declared. The Semaphore knows which districts are meant to be affected and for how long. Observers must infer this from artefacts alone. This is acceptable for experimentation, but it complicates the Department’s task of distinguishing between ordinary noise, recoverable incidents, and signals of deeper control‑plane concern.

Third, the more subtle exercises, particularly those touching the Registry itself, are intentionally quiet. They do not produce spectacular outages. Instead, they manifest as legitimacy failures: routes that ought to be accepted are not, trust decisions that differ by district, authority that appears intact yet behaves inconsistently. From a defensive standpoint, this is the most concerning class of behaviour, precisely because it does not announce itself.

The Department’s assessment is therefore not that the exercises are unreliable, but that their lessons are easy to miss unless one already knows where to look.

From a stability perspective, this suggests a defensive gap. Our current observational tools and habits are well suited to detecting misdelivered letters. They are far less comfortable with noticing when the Registry has been altered, especially if that alteration is partial, selective, or politically inconvenient to acknowledge.

A modest improvement would be to accompany each Semaphore exercise with a short, sealed description of its intended envelope: affected districts, expected duration, and invariants (including what is not expected to happen). This would not constrain the experiment, nor would it alert the public. It would, however, allow the Department to assess whether our defences are failing because the city is vulnerable, or because we are looking in the wrong place.

In summary, the Scarlet Semaphore is succeeding in exploring how fragile our assumptions are. The Department of Silent Stability is learning, though sometimes after the fact, where our defensive thinking remains too focused on traffic and insufficiently focused on authority.

This information, I believe, is precisely what Your Excellency wished to obtain.

Respectfully submitted,

An obedient servant of the city, charged with watching the ledgers rather than the crowds