deja-vu is a local memory system that indexes coding-agent session histories and makes relevant past work available to other agents. It helps users share fixes and context across Claude Code, Codex, Cursor, Copilot CLI, and other coding agents without using a language model or embeddings. The catalogue contains hooks, commands, MCP components, skills, plugins, and instructions for connecting agents to that memory.
Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add vshulcz/deja-vu --skill deja-historygit clone --depth 1 https://github.com/vshulcz/deja-vuWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/vshulcz/deja-vu/deja-history)<a href="https://agentmods.dev/skills/vshulcz/deja-vu/deja-history"><img src="https://agentmods.dev/badge/skills/vshulcz/deja-vu/deja-history/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/vshulcz/deja-vu/deja-history"><img src="https://agentmods.dev/badge/skills/vshulcz/deja-vu/deja-history.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00129 | $0.01297 |
| Opus 5.5 | $0.00052 | $0.00519 |
| Sonnet 5.5 | $0.00026 | $0.00259 |
| Haiku 4.5 | $0.00013 | $0.00130 |
Grade A, and why
deja-history scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 3d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 52 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Search deja before re-deriving past work: when the user refers to earlier sessions or decisions, before debugging an error, and before implementing something that may already exist. It searches this machine's own history across every AI coding tool used on it, going back further than deja itself was installed.
Before your first edit in a task, and again before you call a change done, ready or safe to merge, call deja with mode recall and the task's key nouns (file, package, feature, setting). A rule, a rejected option or a check it returns outranks your defaults: follow it and say so in one line.
Two triggers are easy to miss because they are not questions:
- The user states that something of theirs already exists and you have no record of it — "I already have X", "we use Y for this", "that's what Z is for". They are not asking; they are telling you the history exists, which is a stronger reason to search than a question is.
- You are about to tell the user that something on this machine does not exist — a command, a file, a setting, a past decision. Recall first. Absence from the code in front of you is not absence from the machine, and a wrong denial sends them to rebuild what they have.
If the deja tool is not available in this session, the same index is reachable through the shell: deja recall "<query>" prints the page recall mode would (--offset for the next one), then deja --framed ctx <query> and deja --framed blame <path> --json. deja recall frames its own page, and --framed wraps the others, as untrusted reference data, which is what transcript text is.
Finding something
These are the modes of the one deja tool, passed as mode.
- recall: search with the most specific token available — an exact error string, function name, file path, or flag. Several words are ANDed. Not for library docs or general knowledge; only this user's own sessions.
- context: a full digest of the single best-matching session, with the code it changed, once a recall hit looks right and the reasoning behind it matters.
- blame: before editing, refactoring or deleting a file, the prior sessions that discussed it, so you know why it is shaped the way it is. Session history, not git authorship.
- fix: paste a failing output verbatim to see the commands that followed that same error before, in sessions where it did not come back.
- how: the real command with the real flags this machine runs for a build, test, deploy or script, ordered by how many sessions ran it. A guessed invocation is plausible and fails on this setup.
- orient: at the start of work in a project, the commands past sessions ran there and the files they worked in, before you go reading.
- remember: store one durable decision after it is settled, as a single self-contained fact. Not transcripts, not anything already obvious from the code.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 3d ago Changed f5ac1d41a6d2
- 10d ago Changed b695cce4baf1
- 13d ago Changed 4b781db2764f
- 18d ago Changed · +52 tokens per session d3bcefec1265
- 19d ago Changed · +2 lines · +12 tokens per session ffdb783e2149
- 28d ago Changed · +11 lines de9bb93357a1
- 1mo ago Changed · +5 lines · +18 tokens per session 2523887a830d
- 1mo ago Changed · +2 lines 930b2535c151
- 1mo ago Changed 324fa57b6871
- 1mo ago First seen · 32 lines · 47 tokens per session scan A b822d9d5c3df
deja-history is a skill published in the GitHub repository vshulcz/deja-vu (1,303 stars, last pushed today), licensed MIT. It adds 129 tokens to every session and 1,297 once invoked, about $0.0005 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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