ISMB 2026 — Function-COSI

Agentic evaluation of function prediction tools yields qualitative insights into systematic errors

When is a new function-prediction method good enough to deploy?

A complement to CAFA built on AI Gene Review (AIGR)

ISMB 2026 · Function-COSI · github.com/ai4curation/ai-gene-review

ISMB 2026 — Function-COSI

The deployment question

New function-prediction methods appear monthly — protein language models, generative models, agentic reasoning LLMs.

Annotation databases (GO, UniProt) face a concrete, recurring decision:

Should we import this method's predictions into production?

Classical pipelines (InterPro2GO, PANTHER/PAINT, orthology transfer) are traceable: every annotation traces to a curated family → GO mapping.

The new methods are opaque, prolific, and emit free text — not just GO terms.

ISMB 2026 — Function-COSI

CAFA is indispensable — but insufficient for deployment

CAFA (, vs GOA temporal holdout) tracks field-level progress. Three structural gaps for a deployment decision:

  • Metric-level rewards generic, high-frequency terms; lenient toward false positives; rankings flip with protein- vs term-centric scoring.
  • Ground-truth — GOA is not truth: over-annotations, paralog-inherited errors, <1% negative annotations; 58% of human annotations cover 16% of genes.
  • Holdout-set — benchmark composition is set by curation-campaign funding, not the biology you need to annotate.

And the big one: aggregate metrics operate on the bag-of-GO-terms projection — they leave narrative and reasoning unscored.

ISMB 2026 — Function-COSI

The precedent: de Crécy-Lagard et al. 2025 (G3)

Manually reviewed all 453 DeepECTransformer EC predictions for uncharacterised E. coli proteins.

Only 3 / 453 were genuinely novel and correct.

The lasting contribution is the error taxonomy — the structure a curator needs after the aggregate score:

COR correct novel CNN correct but not novel
LSP less precise PLI paralog-incorrect
NPI non-paralog-incorrect REP frequency-biased
UNC uncertain

Every rejection required synthesis — domain architecture, paralog subfamily, pathway presence, in-vitro vs in-vivo, primary literature.

ISMB 2026 — Function-COSI

The synthesis bottleneck

Each de Crécy-Lagard verdict needed a human expert to integrate many lines of evidence.

That does not scale when methods ship monthly and prediction sets run to the thousands.

Our question

Can the synthesis step itself be partially automated?

AI Gene Review (AIGR): LLM curator-agents grounded in a per-gene evidence package, producing structured, traceable synthetic reviews.

AIGR is a complement to, not a replacement for, CAFA.

ISMB 2026 — Function-COSI

The AIGR pipeline

1 · Evidence assembly (per gene, cached & reproducible)
UniProt record · full GO annotation table (QuickGO) · InterPro architecture · cached publications (full text where available; abstract-level otherwise) · orthogonal deep-research report

2 · Curator-agent review (three phases)

  • Annotation-level: each GO term → ACCEPT / KEEP_AS_NON_CORE / MODIFY / REMOVE / MARK_AS_OVER_ANNOTATED / UNDECIDED + verbatim supporting quote
  • Core-function synthesis: free-text summary + proposed terms
  • Prediction review: classify each predicted term with the Expert Synthetic Review taxonomy + error-type tags

3 · Validation — LinkML schema + best-practice checks; every quote must literally appear in a cached publication

Open source · Typer CLI · just targets · browsable at ai4curation.io/ai-gene-review

ISMB 2026 — Function-COSI

The system under test: BioReason-Pro

A two-stage agentic predictor (Fallahpour et al. 2026):

Stage What it is Output
GO-GPT Autoregressive transformer (ESM2 + organism) GO term hierarchy (upstream input)
BioReason-Pro Qwen3-4B fine-tune <think> trace + free-text functional summary
  • SFT variant — more mechanistic depth, more hallucination
  • RL variant — safer, shallower (never fabricates InterPro)

Provenance: the web app's GO panels are upstream GO-GPT output; the HuggingFace catalogue separately documents its structured GO section as BioReason-Pro SFT output.

ISMB 2026 — Function-COSI

Case study 1 — ARGO139 design

  • 139 proteins, 14 species labels
  • Spanning model-organism genes and non-MOD / less-specialized contexts: pseudoenzymes, sigma-factor paralogs, organism-specific regulators, moonlighting proteins, venom enzymes
  • For each gene: BioReason-Pro RL summary + trace, ARGO95 SFT GO terms for the HF subset, agent-adjudicated local AIGR reference
  • References are not independent expert ground truth: 64 COMPLETE, 48 DRAFT, 23 IN_PROGRESS, 4 INITIALIZED
  • ARGO139 is the collected cohort; performance excludes the wrong-input csr-1 case (n=138) and flags seven 2,000-aa truncations
  • A dedicated comparison agent scores two axes (1–5), each with required supporting quotes:
    • Correctness — are the claims accurate?
    • Completeness — do they span the gene's core biology?
  • Plus a per-gene InterPro-label comparison: novel insight, or restatement? (actual GO_REF:0000002 annotations: 92/139)
ISMB 2026 — Function-COSI

Overall scores: safe, but shallow

Correctness 4.0 / 5 · Completeness 2.9 / 5 (n=138)

Score Correctness Completeness
5 70 (51%) 1 (1%)
4 25 (18%) 40 (29%)
3 22 (16%) 51 (37%)
2 14 (10%) 39 (28%)
1 7 (5%) 7 (5%)

51% score 5/5 on correctness, but only one gene (Uggt1) reaches 5/5 completeness.
The failure tail is small but structurally distinctive — not random noise.

Blinded n=20 second review: correctness 80% exact / kappa 0.950; completeness 55% exact / kappa 0.744.

ISMB 2026 — Function-COSI

Selected-case scores differ by organism

Mouse has the highest selected-case mean (4.7), followed by B. subtilis (4.5), rat (4.4), and human (4.3); S. pombe is lowest (3.2). The panel is deliberately uneven, so this is descriptive, not an organism-level performance estimate.

ISMB 2026 — Function-COSI

Eight reproducible model failure modes

Immediately diagnostic to a reader of the narrative.

# Failure mode Example
1 Pseudoenzyme blind spot Epe1 — "JmjC demethylase" despite degenerate active site
2 Localisation defaults to cytoplasm CpxP periplasmic → called cytoplasmic
3 Paralog indistinguishability Fyn ≡ Src; sigF ≡ sigG ≡ sigK
4 Organism-specific biology absent daf-16 generic FoxO, no IIS/dauer/longevity
5 Neo-functionalisation / moonlighting missed Nmnat NAD⁺ enzyme; chaperone role lost
6 Narrative–GO disconnect RidA: protein binding not deaminase activity
7 Cross-kingdom fold bias aprE subtilisin → "human blood coagulation"
8 Generated UniProt-style fabrication Slc5a1 → steroid-sulfate transporter

The biases are architectural — they predict where the model will fail on deployment.

ISMB 2026 — Function-COSI

What the narratives actually look like

RAS2 (yeast, 2/5) — "a Ras-family GTPase … regulating intracellular vesicle traffic converging on the vacuole"
Actually the primary activator of the cAMP/PKA pathway.

Epe1 (S. pombe, 1/5) — "a nuclear histone demethylase … JmjC oxygenase core"
A pseudoenzyme (HVD not HXD); anti-silencing factor via HP1/Swi6.

TOR1 (yeast, 4/4) — "PIKK serine/threonine kinase … HEAT repeats scaffold regulatory assemblies … integrates nutrient & stress cues"
Correct — the FRB + multi-domain architecture enabled pathway-level inference.

ISMB 2026 — Function-COSI

Mostly a narrative restatement of InterPro labels

The dominant mode across 139 genes: translate InterPro domains into prose, no new biology. Where a family label or actual InterPro2GO mapping is misleading, BioReason-Pro can recapitulate and amplify it.

Adds genuine value only when multi-domain architecture is diagnostic:
TOR1 · NOTCH1 · PTEN · EGFR · spo0A · (informative family names: Uggt1, KAR2, bst1)

A method can average 4.0/5 correctness while providing little net annotation value when it mainly restates supplied domain labels.

ISMB 2026 — Function-COSI

Supplemental review: GOA agreement ≠ biological validity

GO-GPT run directly on 300 genes; overlap measured against three progressively stricter references:

The 3-fold gap between raw-GOA agreement (11.7%) and agent-adjudicated core-function agreement (3.9%) illustrates the difference between snapshot agreement and coverage of the local core-function reference.

ISMB 2026 — Function-COSI

ARGO95 SFT terms: most calls are not novel

955 SFT HF-catalogue terms (95 ARGO139 genes), audited against current GOA/AIGR and targeted biological review:

71.0% CNN (correct/non-novel; 631 exact GOA) · 15.9% NPI/PLI/REP · 2.5% COR · 4.6% LSP · 6.0% UNC

The 2.5% COR are known-literature gaps, not discoveries of previously unknown biology.

ISMB 2026 — Function-COSI

The two arms fail independently

BioReason-Pro's narrative and its GO-term list are generated semi-independently — and can disagree:

  • RAS2 — GO terms correctly predict adenylate cyclase activation (GO:0007190); narrative wrongly describes vesicle trafficking.
  • CpxP — GO terms correctly place it in the periplasm (GO:0030288); narrative wrongly says cytoplasm.

Neither the narrative nor the term list can be trusted in isolation — a deployment protocol must evaluate both. CAFA metrics see only the term list.

(SFT-specific risk: 16% of SFT outputs fabricate fake "UniProt Summary" text for uncharacterised proteins.)

ISMB 2026 — Function-COSI

Case study 2 — ESR-ECOLI-DET-Mini

7 E. coli genes spanning all classes; AIGR reproduces the published taxonomy.

Not blinded: the project artifacts include the published expert labels/rationales.

Dataset ID: 10.5281/zenodo.20751016

Gene Paper AIGR Recovered rationale
ygfF COR COR SDR family; GDH activity confirmed
yciO PLI PLI TsaC paralog; ~10⁴× weaker activity
yegV PLI PLI Correct sugar-kinase EC prefix; substrate unknown
yjhQ NPI NPI Mycothiol pathway absent from E. coli
yrhB NPI NPI QueD already encodes activity; Imm35 domain
yjdM UNC UNC In-vitro activity, no in-vivo phenotype
fepE REP REP No HK similarity; Wzz O-antigen regulator

7 / 7 classifications + mechanistic rationales reproduced. This is a positive control for the schema/workflow, not a blinded accuracy estimate.

ISMB 2026 — Function-COSI

Answer-key withheld recap: useful, not expert-equivalent

A separate literature/bioinformatics-assisted run excluded the de Crécy-Lagard paper and published rationales.

Gene Expert Withheld run Interpretation
fepE REP REP Frequency-bias smell test recovered
yciO PLI PLI Paralog-overannotation recovered
yjhQ / yrhB NPI NPI Pathway-context failures recovered
yegV / ygfF PLI / COR UNC Conservative misses
yjdM UNC NPI Too harsh on in-vitro vs in-vivo boundary

4 / 7 exact labels. Good enough to triage suspicious sequence-AI predictions; not a substitute for expert boundary judgments.

ISMB 2026 — Function-COSI

A three-tier framework for evaluation

Tier What Scales? Grades narrative?
1 · Aggregate (CAFA /) GOA temporal holdout ✓ 10⁴ proteins
2 · Expert / agentic review (AIGR) Per-gene synthesis + taxonomy partially automated
3 · Prospective experiment Assays, genetics, microscopy ✗ no protocol n/a
  • Tier 1 can't tell "adds new biology" from "restates supplied domain labels."
  • Tier 3 doesn't scale — "function" is multi-dimensional & organism-specific.
  • Tier 2 is the practical level for deployment decisions — AIGR brings its cost toward Tier 1.

Recommendation: report a Tier-1 score and a Tier-2 agentic biological-validity score.

ISMB 2026 — Function-COSI

Conclusions

BioReason-Pro mostly tells you what you already know, occasionally something correct GOA has not recorded, and assigns 15.9% of ARGO95 terms to incorrect classes in predictable, diagnosable ways.

  • Narratives restate InterPro labels; eight recurrent model-output failure modes
  • GO terms: 71.0% not novel, 15.9% NPI/PLI/REP, 2.5% correct and absent from frozen GOA in ARGO95
  • Narrative and term arms fail independently → not ready for unsupervised import

The most valuable thing a foundation model can produce is a well-reasoned narrative — it can be reviewed, corrected, combined. Naked GO terms cannot.

Agentic Tier-2 review reads narratives, surfaces systematic failures, separates novelty from restatement — and is already useful as a triage/smell-test layer, even though expert-level nuance remains human.

ISMB 2026 — Function-COSI

Thank you

Data, reviews, pipeline, schema & validator — all open:
github.com/ai4curation/ai-gene-review

Browse 139 BioReason-Pro reviews + ESR-ECOLI-DET-Mini:
ai4curation.io/ai-gene-review

de Crécy-Lagard et al. 2025 (G3, PMID:40703034) · Fallahpour et al. 2026 (bioRxiv 10.64898/2026.03.19.712954)

Talk in one line: aggregate metrics tell you the field is improving; they don't tell a database lead whether to import a given method's predictions. We propose partially-automated agentic review to answer that.