Watch for

Contract

Field	Bound contract
Trigger	User wants to observe a changing surface and receive anomaly judgments, or poll a changing target until a completion predicate holds.
Authority	Read-only: local reads of the bounded surface at each sampling interval. No remote mutation.
Side effect	Local reads of the bounded surface; a terminal completion verdict in until mode.
Done	The stop condition is met and a final summary is emitted (watch mode), or a terminal classification is returned (until mode).

Inputs

• Mode (required): watch (default) or until.
• Surface address / Target (required): the file, URL, log, or artifact to observe or poll.
• Anomaly criteria (required for watch): the condition, pattern, threshold, or structural rule that classifies a sampled state as anomalous.
• Completion predicate (required for until): a falsifiable condition evaluated against the current observed state of the target each poll.
• Sampling / poll interval (required): time between reads, as a number of seconds, a cron expression, or an event-driven trigger name.
• Stop condition (required for watch): a predicate that ends the watch automatically, or an explicit tick count after which the watch stops.
• Deadline or maximum poll count (required for until): bounds the watch. The watch stops at whichever comes first.

Procedure

1. Bound the surface and select the mode. Record the address, the interval, and the mode-specific control (anomaly criteria for watch, or completion predicate and deadline/max-poll for until). Refuse to observe anything outside the declared scope. Done when: mode, address, interval, and control are recorded.
2. Capture the initial state. Read the surface once. Done when: the baseline snapshot is recorded.
3. Wait the interval and sample the surface. If the surface is unreadable, emit an error judgment (watch) or stop and report blocked with the last known state (until); in watch, wait for the next interval rather than widening scope. Done when: a sample is read or an error/blocked judgment is emitted.
4. Evaluate the mode-specific condition.
   • Mode watch: compare the sample against the baseline using the anomaly criteria. Classify the sample as normal, anomalous, error, or stale. Emit a judgment containing the address, timestamp, what changed or why the read failed, and severity if anomalous. Update the baseline to the current sample.
   • Mode until: evaluate the completion predicate against the current observed state. If it holds, stop and report predicate-holds with the final state. Done when: a judgment is emitted or the predicate result is known.
5. Check the terminal condition.
   • Mode watch: if the stop condition is met, end and emit a final summary (total ticks, anomaly count, error count, final surface state). Otherwise repeat from step 3.
   • Mode until: if the deadline or maximum poll count is reached, stop and report non-converged with the last observed state and the number of polls performed. If the same two or more distinct states repeat in a cycle of 3 consecutive polls without the predicate holding, stop and report non-converged with the oscillation pattern. Otherwise repeat from step 3. Done when: a terminal result is emitted.

Failure and recovery

Failure class	Mode	Behavior
Surface unreadable	watch	Emit an error judgment naming the surface and failure reason. Wait for the next interval. Do not widen scope or invent data.
Stale sample	watch	Mark the judgment as stale-data. Continue watching. Do not suppress the tick.
Scope-widening requested	watch	Refuse. The surface was bounded at step 1. Report the refusal and continue on the declared surface.
Stop condition unreachable	watch	Emit a warning and continue until manual stop.
Target unreadable or disappeared	until	Stop. Report blocked with the read failure and the last known state. Do not restart or recreate the target.
Predicate unparseable or ambiguous	until	Stop. Report blocked with the ambiguity. Do not infer a different predicate.
Deadline or maximum poll count reached	until	Stop. Report non-converged with the last observed state and the number of polls performed.
Target state oscillates	until	Stop. Report non-converged with the oscillation pattern, the last observed state, and the oscillation count.

No failure class causes the watcher to pretend the done predicate holds. Every poll produces a judgment or an explicit error.

Output

• Mode watch: a stream of per-tick judgments (surface address, timestamp, classification: normal/anomalous/error/stale, what changed or why the read failed, severity if anomalous), with a final summary on stop: total ticks, anomaly count, error count, and final surface state.
• Mode until: one terminal classification: predicate-holds (with final observed state), non-converged (with last observed state, poll count, and the failure class that stopped it), or blocked (with the failure reason and last known state).