The attention view is inert on any machine that is not M5 or M1

[justin808]

Problem

The attention model recognises exactly two machines. normalizeHost in src/server/attention/buildAttentionModel.ts:

const folded = asciiUpper(value.trim());
return folded === "M5" || folded === "M1" ? folded : null;

A record whose host_id is anything else is not merely labelled unknown — its card is dropped:

`Record ${idText(record)} names host ${quoted(...)}, which is neither M5 nor M1; the card is suppressed.`

and the same function decides the payload's dashboard_host, so a dashboard whose AGENT_COORD_MACHINE_ID is not M5 or M1 reports dashboard_host: "UNKNOWN" and emits a dashboard_host_unknown diagnostic on every read.

The consequence for anyone who is not running this specific two-machine setup: the Human Attention view is inert. Every card is suppressed, the page shows the empty state, and the only hint is a diagnostic naming two machine identifiers that mean nothing to them. This package is published under MIT and installed by name, so "M5" and "M1" are, in effect, a private allowlist shipped as product behavior.

Why this is filed rather than fixed in place

The two-host union is the approved design from issue #125 and the 2026-09-04 design, and it is load-bearing in the shared types (AttentionCardHost), the model, the client's render allowlist, and the cross-host "open on M5:" affordance. Widening it is a product decision with a real design question behind it, not a patch.

The design question

What is a host, once it is not a fixed pair? Candidates, roughly in increasing order of work:

1. Configured allowlist. AGENT_COORD_KNOWN_HOSTS (defaulting to the current pair for compatibility) with the same normalisation and suppression rules. Smallest change; keeps the closed-set guarantee that makes the render allowlist safe.
2. Any well-formed host identifier, bounded and projected like every other untrusted string, with dashboard_host compared case-folded. Suppression then applies only to records with no usable host at all. Removes the allowlist but requires deciding the identifier's shape and its render bound.
3. Dashboard-relative only. Keep the local machine id as the only privileged value: a card is "here" or "elsewhere", and "elsewhere" prints the record's projected host string.

Option 1 unblocks other users with the least risk. Option 3 is probably where this wants to end up, because it makes the concept relative rather than enumerated.

Evidence

• src/server/attention/buildAttentionModel.ts — normalizeHost, the unknown_host suppression path, and dashboardHost.
• src/shared/attention.ts — AttentionCardHost as the literal union.
• Verified at main 6bdf70726f7accc4ad31e19cda51e56a903fe21d.

Found by the post-merge audit of batch acd-attention-1a-20260906 (tracker #134).

[justin808]

One clarification, so this issue is not read as blaming the wrong variable. Two different rules in buildAttentionModel are involved, and only the first one empties anything:

• A record whose host_id is neither M5 nor M1 is suppressed and never becomes a card. This is the rule that makes the feature inert elsewhere: an agent running on a third machine writes its own host into the record, so every card it produces is dropped.
• A dashboard whose own AGENT_COORD_MACHINE_ID is unset or unrecognised keeps every card. It only loses the ability to say which cards are answerable where it runs: dashboard_host becomes UNKNOWN, every card gets host_matches: false, and dashboard_host_unknown and cross_host_count are added.

The widening options in the description are unchanged, and the first rule is still what they need to address. Caught by both reviewers on PR #163 when I made the same conflation in the README.