Context Diet

A Codex plugin that asks TypeSafe's Jev which bulky tool results the session still needs, then replaces the rest with a bounded head and a one-line note. It works at the moment a result is produced, before those results get re-sent on every later request.

Compaction runs after the context is already bloated. Long sessions fill with test logs, build noise, large file reads and MCP payloads that Codex re-sends until compaction summarises them away; this plugin acts when output arrives, and it only looks at big outputs — roughly a page and a half of dense text and up.

PostToolUse fires after a tool produces output and the adapter reads one JSON payload on stdin. Results are left alone when they are small, come from apply_patch, name a tool in neverDietTools, or are the first result of a session; everything else goes to Jev in one request carrying five literal questions.

Codex replaces the tool result with the first truncateHeadChars characters and a note naming what ran and how much was dropped — the README's example replaces 18,422 characters of Bash output with a 300-character head. The model can simply re-run the tool if it needs the rest.

An injection verdict never blocks and never edits: it forces the result to be kept and adds one line of developer context — for example, Bash output scored 0.91 for agent-directed text, flagged as untrusted data. The README's principle is that a false positive must not change what the model can see.

Deterministic: size gates, duplicate detection, redaction, capsules, recovery scoring, statistics and doctor. Jev supplies one semantic signal per judgment and never acts on its own — deterministic code decides what to do with it, and Codex performs the replacement. The prompt guard and Stop quality guard are experimental, shipping off by default.

Three shapes and nothing else: a block decision with a reason and additionalContext when a result is replaced; an additionalContext-only object with no decision field when Codex should add developer context and leave the result intact; and {} for keep, every error and every exempt case. Every decision, including keep, lands in the per-session digest cache.