nika-debugging

Debugging Nika runs

Every run writes a hash-chained journal to .nika/traces/. That journal is the ONLY truth about what happened — debug from the trace, never from a memory of the terminal scroll.

The forensic loop (evidence first)

0. A failed run already names its trace: the card's autopsy: line carries the FULL trace path — start there when you have it.
1. Locate the run: nika trace ls — age · size · workflow · terminal state (completed/failed/paused) · ★ marks the newest trace of each workflow (the resume candidate). Address a trace by its store path — .nika/traces/<name> — everywhere below (ls prints bare names; the readers take the path form on every version).
2. Read the card: nika trace show <trace> — the final verdict, the waves, per-task outcome. nika trace replay <trace> re-renders the run live (replay = re-render, NEVER re-execute).
3. Find the failing task: nika trace outputs <trace> — verb · duration · tokens · a bounded preview per task (full value: nika trace peek). The first red task is the root; everything downstream is fallout.
4. Decode the finding: nika explain NIKA-XXXX teaches the cause · category · fix-form of any code the trace carries.
5. Re-audit the file: nika check <file> — a run that failed often fails again at check once you know what to look for (a model that no longer resolves, a missing env var, a permits violation).
6. Fix minimally, rerun surgically (below). Re-check before any rerun.

Prompts and confirm gates (paused OR failed — same answer line)

On a terminal, nika:prompt blocks and waits (the run shows as paused in nika trace ls). Headless — which is where an agent lives — a prompt without a default: FAILS with NIKA-BUILTIN-PROMPT-001 instead. Both states resolve with the same line:

nika run <file> --resume <trace> --answer <task>=<value>

Confirm gates take booleans (--answer approve=true); every task the journal already proved is skipped as a visible cache hit, so only the prompt and its downstream run. Removing a paused trace refuses without --force and names the prompt it would destroy — that refusal is protecting an answer, not being difficult.

A failed run's card prints its own forensics line (autopsy: nika trace peek <trace> <task>) — start there, it points at the exact failing task.

Surgical reruns (never restart what already worked)

• nika run <file> --from <task-id> — rerun from one task onward, keeping upstream results.
• nika run <file> --task <task-id> — rerun exactly one task.
• After an intentional behavior change, refresh the pin: nika test <file> --update rewrites the golden from an offline mock run — never hand-edit a .golden.json to make red green.

Common root causes (check these before anything exotic)

• Model does not resolve: nika check <file> --json → models_resolve says whether every model: runs in THIS binary; nika catalog names the env var each provider needs.
• Missing credential: secrets ride ${{ secrets.X }} / ${{ env.KEY }} — the trace shows the task, the shell shows the env. nika doctor audits the machine side.
• Timeout too tight: local providers need timeout: "300s" or more — thinking models routinely think past 30s.
• Permits violation: the run was blocked by its own declared boundary — read the finding, then either the task is wrong or the boundary is (widen it consciously, never delete it).
• Cost cap hit: --max-cost-usd blocks BEFORE the call that would cross the cap — that is the feature working, not a bug. Raise the cap deliberately or shrink the task.

Tamper evidence

nika trace verify <trace> checks the hash chain: any edited, inserted, dropped or reordered line breaks every hash after it. Exit 0 intact · 2 broken · 3 unchained (pre-chain journal). Cite the trace in any report — a verified chain is proof, prose is not.

Honesty lines

• The trace tells you what the engine did. It cannot tell you WHY a provider returned garbage — a provider-side outage or a model regression is named as a hypothesis, never asserted as fact.
• Never edit a trace. Never delete a paused trace to "clean up".
• If the binary is missing: brew install supernovae-st/tap/nika — do not reconstruct runs from memory.