Kjell Tore Guttormsen
bdcb1f1080
The corpus goes 83 -> 89 and scope_covered gains signatures/active-content.json.
The blocker in STATE dissolved under measurement, the same way last session's
13-pattern one did. "An id space for carriers/active-content/secret-egress" was one
question in name only; the three tables have three unrelated problems:
- active-content needed NO id space invented. label_format ("active:{class}") and the
constructs keys were already extracted verbatim from the seed runtime, and their
concatenation IS what it emits - verified by comparing the six keys to the six class
strings at its _flag call sites. What blocked these cases was never naming; it was
spec section 1, fixed in the parent commit.
- carriers has no adoptable id space AND an entry-point dependence underneath it.
- secret-egress is not an id question at all: the two runtimes carry DIFFERENT tables.
18 entries here against the guard's 25, cut at different granularities - this file's
single `GitHub Token` is four ids there, `Private Key PEM Block` three, `Database
connection string` four - with membership diverging both ways. `aws-access-key-id`
is the one clean 1:1, which is why exactly one egress case was ever offered. That
number was a symptom, not modesty.
Both blockers are now recorded under scope_planned.blockers, measured, replacing a
blanket "no runtime has agreed to an id space" that was wrong for both.
Generated from measurement, not written. Payloads were extracted from the seed
runtime's coverage.py by AST - evaluating each _scan_case argument in that module's
own namespace rather than retyping detection data - then run through its public
output gate, the same entry point the 83 lexicon cases used. The fixtures were then
re-read from disk by a separate checker that re-computed every digest, re-scanned the
bytes and applied exact-within-scope independently of the generator: 6 cases, 0
failed checks.
Six built from seven offered. The runtime's matrix drives two payloads at
`active:markdown-image`; measured, their in-scope finding sets are identical, and the
second's only distinguishing signal (entropy:base64-blob) falls outside every table
this repository publishes. Dropped rather than given a discriminated case id, and
named under omitted_payloads so the count reads as a decision.
These six prove LESS than the 83, and the manifest says so: their payloads come from
the only runtime implementing the table, so no second implementation's agreement
could be measured. They pin one runtime's behaviour as a contract a future
implementer can be held to - less than cross-runtime agreement, more than nothing.
llm-security's absence of the table is measured at b0de0ca, not assumed: a tree-wide
search finds no implementation, and `git log -S` over --all returns zero commits,
closing the "it was there once" reading. Absent table is not absent capability -
their entropy scanner reaches markdown-image URLs by another route - and the manifest
says that too.
Provenance and measurement for the active-content half are kept in their own blocks:
a different source structure at a different commit, and one pin must not stand for
two measurements. The guard's HEAD moved twice during the work (3c56d50 -> de09711 ->
398eb74); measurement ran at de09711 and the drift is recorded, including that
active_content.py is NOT identical to the 0bf0729 the data file pins - the change
adds a scan-cap self-safety finding and touches no construct.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CVouC9nsfrfV5jRSejxbvQ
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||
|---|---|---|
| calibration | ||
| codepoints | ||
| conformance | ||
| docs | ||
| lexicon | ||
| mapping | ||
| schema | ||
| signatures | ||
| spec | ||
| .gitignore | ||
| CHANGELOG.md | ||
| CLAUDE.md | ||
| LICENSE | ||
| README.md | ||
llm-security-commons
Runtime-neutral core for LLM and agent security detection: detector data, normative contracts and a conformance corpus that several runtimes can share.
Detection logic gets reimplemented every time it crosses a language boundary, and the copies drift: the Node scanner flags a zero-width carrier the Python guard misses, and nobody notices until an incident. This repository holds the part that should never have been copied — the pattern tables, the code-point carriers, the calibration thresholds, the finding contract, and a fixture corpus with expected verdicts — so that two independent implementations can be held to the same answer on the same input.
It is for anyone building or maintaining a detector for prompt injection, secret egress, unicode-carrier smuggling or active content in untrusted text, on any runtime.
It holds no runnable code. Data, specifications and fixtures only.
Install
Nothing to install — this repository is vendored into consumers, not installed.
As a git subtree (recommended: history is preserved and upgrades are a single command):
git subtree add --prefix vendor/commons \
https://git.fromaitochitta.com/open/llm-security-commons.git v0.1.0 --squash
# later, to move to a newer tag
git subtree pull --prefix vendor/commons \
https://git.fromaitochitta.com/open/llm-security-commons.git v0.2.0 --squash
Or pin a tag and copy — fork-and-own is an explicitly supported path:
git clone --depth 1 --branch v0.1.0 \
https://git.fromaitochitta.com/open/llm-security-commons.git
Always vendor a tag, never main. The tag is what a conformance result can be
attributed to.
Requirements
A JSON parser and the ability to read a text file. That is the entire dependency surface, and keeping it that small is the point.
What it does
| Path | Contents |
|---|---|
lexicon/injection-lexicon.json |
Prompt-injection pattern lexicon: 83 patterns in four severity families (critical, high, medium, hybrid), each with a stable id and per-runtime aliases. The thematic class (override:, evasion:, hitl-trap:, …) is the id prefix, not the family. |
codepoints/carriers.json |
Invisible and deceptive carriers: zero-width characters, BIDI controls, Unicode Tag block ranges, and the homoglyph map. |
signatures/secret-egress.json |
Credential and token shapes that must never leave a machine, in a portable regex dialect. |
signatures/malware-signatures.json |
Known-bad identity for the malicious-code class (SIG): seven tight signatures over four families — PHP webshells, reverse shells, cryptominers, offensive tooling. Seven signatures are not malware coverage, and the file says so. |
signatures/active-content.json |
Active content that renders or fetches on its own — Markdown images, links, reference definitions and autolinks, data: URIs, active HTML. The EchoLeak class. |
calibration/calibration.json |
The numbers a detector must not invent: risk-score tier constants, verdict thresholds, risk-band cutoffs, posture grade thresholds. Transcribed from a prose summary, not differentially verified — the file says so itself. |
mapping/owasp-map.json |
Finding-id prefix → OWASP taxonomy entry (LLM / ASI / AST / MCP). |
schema/finding.schema.json |
Normative. The finding contract — closed against its producer, ten properties — plus the SARIF output profile. The JSONL profile is recorded as not applicable, with the reason. |
spec/conformance-corpus.md |
Normative. How to read the corpus: what a case is, why input.txt is bytes rather than text, and what exact-within-scope requires of a runtime. |
conformance/ |
89 cases. One directory per case: input.txt in, expected.json out. Ground truth. 83 cover the injection lexicon, one per pattern, and both seeding runtimes were measured producing the same verdict on all 83. Six cover active content and are measured against the one runtime that implements that table — not-applicable for the other, not failing. See conformance/manifest.json. |
spec/decode-pipeline.md |
Planned, not in v0.1.0. The decode order, in RFC 2119 language. Two runtimes that decode in different orders will disagree on identical input. Writing it needs the decode implementation, which is engine code and has not been supplied — and a normative spec guessed from a data dump would be worse than an absent one. |
docs/extraction-plan.md |
Informative: where each file was seeded from, and what v0.1.0 promised. |
docs/lexicon-port-divergence.md |
Informative: a measured disagreement between two ports of the injection lexicon — 13 patterns that behave differently, in both directions, and why no data file was changed because of it. |
Every JSON file carries a top-level version. Every normative specification carries a
Status: normative marker. Rows marked Planned are named here because the layout is
part of the contract, but the file does not exist yet — they are not links, and nothing in
v0.1.0 depends on them.
Each data file records its own provenance and, in verified, how strongly it is backed.
calibration/calibration.json is currently the one file that says false: it was
transcribed from a prose summary rather than diffed against a running implementation.
How a consumer proves it conforms
Run every conformance/<case>/input.txt through your detector and compare the finding ids
to expected.json — exactly, but only within the data files the case names in scope.
spec/conformance-corpus.md is the normative reading;
the short version is that a runtime must raise every listed finding and no other finding
from the same table, and that what it does with tables outside the case's scope is not
compared.
Disagreement means your runtime is wrong, or the fixture is — and the fixture only changes in its own commit, with the reason written down.
There is no CI in this organisation and nothing runs that comparison automatically. It runs in each consumer's own test suite, against a pinned tag.
The corpus covers two tables, and they do not carry equal weight — treating them as one number would misreport both:
lexicon/injection-lexicon.json— 83 cases. Both seeding runtimes implement it and both ratified its id space.signatures/active-content.json— 6 cases. One runtime implements it. For a runtime that does not, these cases arenot-applicable, a third verdict beside pass and fail: a runtime declares which commons data files it implements, and a case scoped outside that set was never addressed to it. See §1.1 — and note thatnot-applicablesays the corpus did not ask, never that the runtime is blind.
Four cases remain unshipped, for the carrier and secret-egress tables, and neither is
blocked on effort. Carriers has no adoptable id space: one runtime labels the same carrier
differently depending on pipeline stage, which would make a case's verdict depend on the
entry point it was measured through. Secret egress is not an id question at all — the two
runtimes carry different tables, 18 entries against 25, cut at different granularities.
conformance/manifest.json records both blockers under scope_planned.blockers, measured,
so the gap is visible rather than inferred.
Non-goals
- Not a scanner. There is no engine here, and there will not be one. If you are looking
for something to run, you want a consumer —
llm-securityfor Claude Code. - Not a framework or a library. No package manifest, no dependencies, no build.
- Not a general-purpose Unicode or regex toolkit. The tables cover what the detection classes need, not the standard.
- Not a vulnerability feed. No CVEs, no advisories, nothing time-sensitive. Everything here is offline and deterministic.
- Not a policy engine.
calibration.jsonpublishes the thresholds; deciding what to do when one is crossed belongs to the consumer. - Not the place to fix a consumer's behaviour. Data extracted from an implementation is kept behaviour-identical on purpose. A disagreement is reported to that implementation and decided there, where it is tested.
Known limitations
- Coverage is the union of what the seed implementations detected, not of what exists. A class absent from the tables above has not been shown to work anywhere.
- The corpus is narrower than the data.
conformance/constrains two of the seven data files. The other five are published, provenance-checked and unfixtured: a runtime can pass every case and still readcalibration.jsonwrongly. Passing the corpus is evidence about the injection lexicon and about active content, and about nothing else. - A pass count is unreadable without the declared table set. A runtime implementing one
table and a runtime implementing four can print the same number.
not-applicablecases must be reported, not dropped from the denominator —76/83and76 passed, 6 not-applicabledescribe different runtimes. - The six active-content cases prove less than the 83. Their payloads come from the only runtime that implements the table, so no second implementation's agreement could be measured. They pin one runtime's behaviour as a contract a future implementer can be held to; they are not cross-runtime agreement.
- Regex portability is a real risk. Pattern data is written for a common subset, but engines differ (lookbehind, named groups, Unicode property escapes). A consumer whose engine rejects a pattern must report it rather than silently skip it — a skipped pattern is an invisible false negative.
- Fixtures prove agreement, not correctness. Two runtimes passing the same corpus agree
with each other and with the fixture author. A wrong
expected.jsonmakes both wrong identically. - The homoglyph map is finite. Confusable coverage is a long tail; absence from the map is not evidence a character is safe.
Changelog
See CHANGELOG.md.
License
MIT — see LICENSE. Fork-and-own is an intended use, not a tolerated one.