anno

Text annotation and entity extraction. Covers NER, coreference resolution, PII detection, relation extraction, and export to standard formats.

Multiple backends (ML, statistical, rule-based) are tried at runtime; works without model downloads via built-in fallbacks.

Dual-licensed under MIT or Apache-2.0. MSRV: 1.88.

Quickstart

[dependencies]
anno = "0.6.0"

let entities = anno::extract("Sophie Wilson designed the ARM processor.")?;
for e in &entities {
    println!("{} [{}] ({},{}) {:.2}", e.text, e.entity_type, e.start(), e.end(), e.confidence);
}
// Offline (heuristic only):
//   Sophie Wilson [PER] (0,13) 0.60
//   ARM [ORG] (27,30) 0.55
// With `onnx` enabled and default models cached, the ML backends raise
// confidences and add entities. `ANNO_NO_DOWNLOADS=1` blocks new
// HuggingFace fetches but still loads cached or locally-exported models.
# Ok::<(), anno::Error>(())

Filter results with prelude (re-exports common types including Result):

use anno::prelude::*;

# let entities = anno::extract("Sophie Wilson designed the ARM processor.")?;
let people: Vec<_> = entities.of_type(&EntityType::Person).collect();
let confident: Vec<_> = entities.above_confidence(0.8).collect();
# Ok::<(), Error>(())

For backend control, construct a model directly:

use anno::{Model, StackedNER};

let m = StackedNER::default();
let ents = m.extract_entities("Sophie Wilson designed the ARM processor.", None)?;
# Ok::<(), anno::Error>(())

StackedNER::default() selects the best available backend at runtime: BERT ONNX and NuNER (both tried independently when onnx enabled and models cached), then GLiNER if neither loaded, falling back to pattern + heuristic extraction. Set ANNO_NO_DOWNLOADS=1 to disable new HuggingFace downloads; cached models and any backend loaded from a local path (from_local / ONNX export scripts) continue to work.

Zero-shot custom types via GLiNER:

use anno::GLiNEROnnx;

let m = GLiNEROnnx::new("onnx-community/gliner_small-v2.1")?;
let ents = m.extract("Aspirin treats headaches.", &["drug", "symptom"], 0.5)?;
for e in &ents {
    println!("{}: {}", e.entity_type, e.text);
}
// drug: Aspirin
// symptom: headaches
# Ok::<(), anno::Error>(())

Custom backends

AnyModel wraps a closure into a Model, bypassing the sealed trait when you need to plug in an external NER system:

use anno::{AnyModel, Entity, EntityType, Language, Model, Result};

let model = AnyModel::new(
    "my-ner",
    "REST API wrapper",
    vec![EntityType::Person, EntityType::Organization],
    |text: &str, _lang: Option<Language>| -> Result<Vec<Entity>> {
        Ok(vec![]) // call your backend here
    },
);
let ents = model.extract_entities("test", None)?;
# Ok::<(), anno::Error>(())

PII detection

Classify NER entities as PII and scan for structured patterns (SSN, credit card, IBAN, email, phone). Redact or pseudonymize in one call:

use anno::{pii, Model, StackedNER};

let text = "John Smith's SSN is 123-45-6789.";
let m = StackedNER::default();
let redacted = pii::scan_and_redact(text, &m)?;
// "[PERSON_1]'s SSN is [ID_NUMBER_1]."
# Ok::<(), anno::Error>(())

Backends

Multiple backends spanning ML (GLiNER, NuNER, BERT, W2NER, TPLinker, GLiRel), statistical (CRF, HMM), rule-based (pattern, heuristic), and LLM-based extraction. ML backends are feature-gated (onnx or candle); weights download from HuggingFace on first use. See BACKENDS.md for the full list, default models, and status.

Feature flags

onnx (default) -- ONNX Runtime backends. candle -- pure-Rust backends, no C++ runtime. metal/cuda -- GPU acceleration (enables candle). llm -- LLM-based extraction via OpenRouter, Anthropic, Groq, Gemini, or Ollama. discourse -- centering theory, abstract anaphora, dialogue acts. analysis -- coref metrics and cluster encoders. schema -- JSON Schema for output types. production -- tracing instrumentation.

CLI

cargo install anno-cli --features onnx

anno extract --text "Lynn Conway worked at IBM and Xerox PARC in California."
# PER:1 "Lynn Conway"
# ORG:2 "IBM" "Xerox PARC"
# LOC:1 "California"

anno extract --model gliner --extract-types "DRUG,SYMPTOM" \
  --text "Aspirin can treat headaches and reduce fever."
# drug:1 "Aspirin" symptom:2 "headaches" "fever"

anno debug --coref -t "Sophie Wilson designed the ARM. She revolutionized mobile computing."
# Coreference: "Sophie Wilson" -> "She"

JSON output with --format json. Batch processing with anno batch. Graph export (N-Triples, JSON-LD, CSV) with anno export --features graph.

Coreference

Three resolvers: SimpleCorefResolver (rule-based, 9 sieves; requires analysis feature), FCoref (neural, 78.5 F1 on CoNLL-2012 [3]; requires onnx), and MentionRankingCoref. FCoref requires a one-time model export: uv run scripts/export_fcoref.py (from a repo clone).

RAG preprocessing (rag::resolve_for_rag(), rag::preprocess()): rewrites pronouns for self-contained chunks after splitting. Always available (no feature flag required).

Scope

Inference-time extraction. Training pipelines are out of scope -- use upstream frameworks and export ONNX weights.

Troubleshooting

• ONNX linking errors: use default-features = false for builds without C++, or check ORT_DYLIB_PATH.
• Model downloads: set ANNO_NO_DOWNLOADS=1 for cached-only mode behind firewalls.
• Feature errors: most backends are gated behind onnx or candle.
• Offset mismatches: all spans use character offsets, not byte offsets. See CONTRACT.md.

Examples

All examples live in crates/anno/examples/. Run with cargo run --example <name>.

References

[1] Grishman & Sundheim, COLING 1996. [2] Tjong Kim Sang & De Meulder, CoNLL 2003. [3] Otmazgin et al., AACL 2022 (F-COREF). [4] Jurafsky & Martin, SLP3 2024. [5] Zaratiana et al., NAACL 2024 (GLiNER). [6] Bogdanov et al., 2024 (NuNER). [7] Li et al., AAAI 2022 (W2NER). [8] Devlin et al., NAACL 2019 (BERT). [9] Lafferty et al., ICML 2001 (CRF). [10] Wang et al., COLING 2020 (TPLinker). [11] Zaratiana et al., 2025 (GLiNER2). [12] Rabiner, Proc. IEEE 1989 (HMM).

Full list: docs/REFERENCES.md. Citeable via CITATION.cff.

License

Dual-licensed under MIT or Apache-2.0.