devtu-optimize-skills

name	devtu-optimize-skills
description	Optimize ToolUniverse skills for better report quality, evidence handling, and user experience. Apply patterns like tool verification, foundation data layers, disambiguation-first, evidence grading, quantified completeness, and report-only output. Use when reviewing skills, improving existing skills, or creating new ToolUniverse research skills.

Optimizing ToolUniverse Skills

Best practices for creating high-quality ToolUniverse research skills that produce detailed, evidence-graded reports with proper source attribution.

When to Use This Skill

Apply when:

• Creating new ToolUniverse research skills
• Reviewing/improving existing skills
• User complains about missing details, noisy results, or unclear reports
• Skill produces process-heavy instead of content-heavy output
• Tools are failing silently or returning empty results

Tool Quality Standards

These principles apply when evaluating or improving the underlying tool implementations (not just the skill layer):

1. Error messages must be actionable — tell the user what went wrong AND what to do. Not "Not found" but "Cancer type 'CLL' is not a TCGA type. Use one of: [BRCA, LUAD, ...]. For CLL data, try CancerPrognosis_search_studies(keyword='CLL')."

2. Schema must match API reality — return_schema field names must match actual API response fields. Run python3 -m tooluniverse.cli run <Tool> '<json>' and compare field names against the schema before publishing.

3. Coverage transparency — descriptions must state what data is NOT included, not just what is. If a tool only covers TCGA cancer types, say so explicitly in the description.

4. Input validation before API calls — validate cancer names, gene symbols, drug names at input. Don't silently send invalid values to the API and return empty results.

5. Cross-tool routing — when a query is out-of-scope, the error message should name the correct tool to use instead.

6. No silent parameter dropping — if a parameter is ignored or unsupported, the response must say so. Never silently discard a user-supplied filter.

Core Optimization Principles

1. Tool Interface Verification (Pre-flight Check)

Problem: Tool APIs change parameter names over time, or skills are written with incorrect parameter assumptions. This causes silent failures - tools return empty results without errors.

Solution: Verify tool parameters before calling unfamiliar tools:

# Always check tool params to prevent silent failures
tool_info = tu.tools.get_tool_info(tool_name="Reactome_map_uniprot_to_pathways")
# Reveals: takes `id` not `uniprot_id`

Maintain a known corrections table in skills that use many tools:

Tool	WRONG Parameter	CORRECT Parameter
Reactome_map_uniprot_to_pathways	uniprot_id	id
ensembl_get_xrefs	gene_id	id
GTEx_get_median_gene_expression	gencode_id only	gencode_id + operation="median"
OpenTargets_*	ensemblID	ensemblId (camelCase)

Rule: Before calling any tool for the first time in a skill, confirm params via get_tool_info() once per tool family, or maintain a vetted param map in the skill.

Why this matters: Retry logic won't help if you're calling a tool with wrong parameter names - it will consistently return empty. This is different from API flakiness.

2. Foundation Data Layer (Path 0)

Problem: Skills query specialized tools for each section independently, missing data that a comprehensive aggregator already has. Results are inconsistent when specialized tools fail.

Solution: Identify if your domain has a comprehensive aggregator and query it FIRST before specialized tools.

Examples by domain:

Domain	Foundation Source	What It Provides
Drug targets	Open Targets	Diseases, tractability, safety, drugs, GO, publications, mouse models
Chemicals	PubChem	Properties, bioactivity, patents, literature
Diseases	Open Targets / OMIM	Genes, drugs, phenotypes, literature
Genes	MyGene / Ensembl	Annotations, cross-refs, GO, pathways

Pattern:

## Workflow
Phase 0: Foundation Data (aggregator query)
Phase 1: Disambiguation (ID resolution, collision detection)
Phase 2: Specialized Queries (fill gaps from Phase 0)
Phase 3: Report Synthesis

Why this works: The aggregator provides reliable baseline data across multiple sections. Specialized tools then add depth or fill gaps, rather than being the sole source.

3. Versioned Identifier Handling

Problem: Some APIs require versioned identifiers (e.g., GTEx needs ENSG00000123456.12), while others reject them. Skills fail silently when using the wrong format.

Solution: During ID resolution, capture BOTH versioned and unversioned forms:

ids = {
    'ensembl': 'ENSG00000123456',           # Unversioned (most APIs)
    'ensembl_versioned': 'ENSG00000123456.12'  # Versioned (GTEx, some others)
}

# Get version from Ensembl lookup
gene_info = tu.tools.ensembl_lookup_gene(id=ensembl_id, species="human")
if gene_info and gene_info.get('version'):
    ids['ensembl_versioned'] = f"{ensembl_id}.{gene_info['version']}"

Fallback strategy:

1. Try unversioned first (more portable)
2. If empty, try versioned
3. Document which format worked

Common versioned ID APIs: GTEx, GENCODE, some Ensembl endpoints

4. Disambiguation Before Research

Problem: Skills that jump straight to literature search often miss target details or retrieve irrelevant papers due to naming collisions.

Solution: Add a disambiguation phase before any literature search:

## Phase 1: Target Disambiguation (Default ON)

### 1.1 Resolve Official Identifiers
- UniProt accession (canonical protein)
- Ensembl gene ID + version (for expression data)
- NCBI Gene ID (for literature)
- ChEMBL target ID (for drug data)

### 1.2 Gather Synonyms and Aliases
- All known gene symbols
- Protein name variants
- Historical names

### 1.3 Detect Naming Collisions
- Search "[SYMBOL]"[Title] - review top 20 results
- If >20% off-topic → identify collision terms
- Build negative filter: NOT [collision1] NOT [collision2]

### 1.4 Get Baseline Profile (from annotation DBs, not literature)
- Protein domains (InterPro)
- Subcellular location (HPA)
- Tissue expression (GTEx)
- GO terms and pathways

Why this works: Annotation databases provide reliable baseline data even when literature is sparse or noisy.

5. Report-Only Output (Hide Search Process)

Problem: Users don't want to see "searched 8 databases, found 1,247 papers, deduplicated to 892..."

Solution: Output structure:

File	Content	When
[topic]_report.md	Narrative findings only	Always (default)
[topic]_bibliography.json	Full deduplicated papers	Always
methods_appendix.md	Search methodology	Only if requested

In the report:

• ✅ DO: "The literature reveals three main therapeutic approaches..."
• ❌ DON'T: "I searched PubMed, OpenAlex, and EuropePMC, finding 342 papers..."

6. Evidence Grading

Problem: A review article mention is treated the same as a mechanistic study with direct evidence.

Solution: Apply evidence tiers to every claim:

Tier	Symbol	Criteria
T1	★★★	Mechanistic study with direct evidence
T2	★★☆	Functional study (knockdown, overexpression)
T3	★☆☆	Association (screen hit, GWAS, correlation)
T4	☆☆☆	Mention (review, text-mined, peripheral)

In report:

ATP6V1A drives lysosomal acidification [★★★: PMID:12345678] and has been 
implicated in cancer progression [★☆☆: PMID:23456789, TCGA expression data].

Required locations for evidence grades:

1. Executive Summary - key disease claims
2. Disease Associations - every disease link
3. Key Papers table - evidence tier column
4. Recommendations - reference evidence quality

Per-section summary:

### Theme: Lysosomal Function (47 papers)
**Evidence Quality**: Strong (32 mechanistic, 11 functional, 4 association)

7. Quantified Completeness (Not Just Categorical)

Problem: "Include PPIs" is aspirational; reports pass the checklist but are data-thin.

Solution: Define numeric minimums for each section:

Section	Minimum Data	If Not Met
PPIs	≥20 interactors	Explain why fewer + which tools failed
Expression	Top 10 tissues with values	Note "limited data" with specific gaps
Disease	Top 10 associations with scores	Note if fewer available
Variants	All 4 constraint scores (pLI, LOEUF, missense Z, pRec)	Note which unavailable
Druggability	All modalities assessed	"No drugs/probes" is valid data
Literature	Total + 5-year trend + 3-5 key papers	Note if sparse (<50 papers)

Why this matters: Quantified minimums make completeness auditing objective and mechanical, not subjective.

8. Mandatory Completeness Checklist

Problem: Reports have inconsistent sections; some topics get skipped entirely.

Solution: Define mandatory sections that MUST exist, even if populated with "Limited evidence" or "Unknown":

## Completeness Checklist (ALL Required)

### Identity & Context
- [ ] Official identifiers resolved (all 6 types)
- [ ] Synonyms/aliases documented
- [ ] Naming collisions handled (or "none detected")

### Biology
- [ ] Protein architecture (or "N/A for non-protein")
- [ ] Subcellular localization
- [ ] Expression profile (≥10 tissues with values)
- [ ] Pathway involvement (≥10 pathways)

### Mechanism
- [ ] Core function with evidence grades
- [ ] Model organism data (or "none found")
- [ ] Key assays described

### Disease & Clinical
- [ ] Genetic variants (SNVs and CNVs separated)
- [ ] Constraint scores (all 4, with interpretations)
- [ ] Disease links with evidence grades (≥10 or "limited")

### Druggability
- [ ] Tractability for all modalities
- [ ] Known drugs (or "none")
- [ ] Chemical probes (or "none available")
- [ ] Clinical pipeline (or "none")

### Synthesis (CRITICAL)
- [ ] Research themes (≥3 papers each, or "limited")
- [ ] Open questions/gaps
- [ ] Biological model synthesized
- [ ] Testable hypotheses (≥3)

9. Aggregated Data Gaps Section

Problem: "No data" notes scattered across 14 sections; users can't quickly see what's missing.

Solution: Add a dedicated Data Gaps & Limitations section that consolidates all gaps:

## 15. Data Gaps & Limitations

| Section | Expected Data | Actual | Reason | Alternative Source |
|---------|---------------|--------|--------|-------------------|
| 6. PPIs | ≥20 interactors | 8 | Novel target, limited studies | Literature review needed |
| 7. Expression | GTEx TPM | None | Versioned ID not recognized | See HPA data |
| 9. Probes | Chemical probes | None | No validated probes exist | Consider tool compound dev |

**Recommendations for Data Gaps**:
1. For PPIs: Query BioGRID with broader parameters; check yeast-2-hybrid studies
2. For Expression: Query GEO directly for tissue-specific datasets

Why this matters: Users can quickly assess data quality and know where to look for more information.

10. Query Strategy Optimization

Problem: Simple keyword searches retrieve too much noise or miss relevant papers.

Solution: Three-step collision-aware query strategy:

## Query Strategy

### Step 1: High-Precision Seeds
Build a mechanistic core set (15-30 papers):
- "[GENE_SYMBOL]"[Title] AND mechanism
- "[FULL_PROTEIN_NAME]"[Title]
- "UniProt:ACCESSION"

### Step 2: Citation Network Expansion
From seeds, expand via citations:
- Forward: PubMed_get_cited_by, EuropePMC_get_citations
- Related: PubMed_get_related
- Backward: EuropePMC_get_references

### Step 3: Collision-Filtered Broad
Apply negative filters for known collisions:
- "TRAG" AND immune NOT plasmid NOT conjugation
- "JAK" AND kinase NOT "just another"

Citation-first for sparse targets: When keyword search returns <30 papers, prioritize citation expansion from the few good seeds.

11. Tool Failure Handling

Problem: NCBI elink and other APIs can be flaky; skills fail silently.

Solution: Automatic retry with fallback chains:

## Failure Handling

### Retry Protocol
Attempt 1 → fails → wait 2s → Attempt 2 → fails → wait 5s → Fallback

### Fallback Chains
| Primary | Fallback 1 | Fallback 2 |
|---------|------------|------------|
| PubMed_get_cited_by | EuropePMC_get_citations | OpenAlex citations |
| PubMed_get_related | SemanticScholar | Keyword search |
| GTEx_* | HPA_* | Note as unavailable |
| Unpaywall | EuropePMC OA flag | OpenAlex is_oa |
| ChEMBL_get_target_activities | GtoPdb_get_target_ligands | OpenTargets drugs |
| intact_get_interactions | STRING_get_protein_interactions | OpenTargets interactions |

### Document Failures
In report: "Expression data unavailable (GTEx API timeout after 3 attempts)"

Rule: NEVER silently skip failed tools. Always document in the Data Gaps section.

12. Scalable Output Structure

Problem: Reports with 500+ papers become unreadable; users can't find what they need.

Solution: Separate narrative from data:

Narrative report (~20-50 pages max):

• Executive summary
• Key findings by theme
• Top 20-50 papers highlighted
• Conclusions and hypotheses

Bibliography files (unlimited):

• [topic]_bibliography.json - Full structured data
• [topic]_bibliography.csv - Tabular for filtering

JSON structure:

{
  "pmid": "12345678",
  "doi": "10.1038/xxx",
  "title": "...",
  "evidence_tier": "T1",
  "themes": ["lysosomal_function", "autophagy"],
  "is_core_seed": true,
  "oa_status": "gold"
}

13. Synthesis Sections

Problem: Reports describe what was found but don't synthesize into actionable insights.

Solution: Require synthesis sections:

## Required Synthesis Sections

### Biological Model (3-5 paragraphs)
Integrate all evidence into a coherent model:
- What does the target do?
- How does it connect to disease?
- What's the key uncertainty?

### Testable Hypotheses (≥3)
| # | Hypothesis | Perturbation | Readout | Expected |
|---|------------|--------------|---------|----------|
| 1 | [Hypothesis] | [Experiment] | [Measure] | [Prediction] |

### Suggested Experiments
Brief description of how to test each hypothesis.

---

Skill Review Checklist

When reviewing a ToolUniverse skill, check:

Tool Contract

• Tool parameters verified via get_tool_info() or documented corrections
• Versioned vs unversioned ID handling specified
• Foundation data source identified (if available for domain)

Report Quality

• Report focuses on content, not search process
• Methodology in separate appendix (optional)
• Evidence grades applied to claims (T1-T4)
• Source attribution on every fact
• Sections exist even if "limited evidence"

Query Strategy

• Disambiguation phase before search
• Collision detection for ambiguous names
• High-precision seeds before broad search
• Citation expansion option for sparse topics
• Negative filters documented

Tool Usage

• Annotation tools used (not just literature)
• Fallback chains defined
• Failure handling with retry
• OA handling (full or best-effort)

Completeness

• Quantified minimums defined per section
• Completeness checklist with checkboxes
• Data Gaps section aggregates all missing data
• "Negative results" explicitly documented ("no probes" not blank)

Output Structure

• Main report is narrative-focused
• Bibliography in separate JSON/CSV
• Synthesis sections required

User Experience

• Progress updates are brief
• No raw tool outputs shown
• Final report is the deliverable

---

Common Anti-Patterns to Fix

1. "Search Log" Reports

Bad: "Round 1: Searched PubMed (234 papers), OpenAlex (456 papers)..." Fix: Keep methodology internal; report findings only

2. Missing Disambiguation

Bad: Search "JAK" and get kinase + "just another kinase" papers mixed Fix: Add collision detection; build negative filters

3. No Evidence Grading

Bad: "Multiple studies show..." (which studies? what quality?) Fix: Apply T1-T4 grades; label each claim

4. Empty Sections Omitted

Bad: Skip "Pathogen Involvement" because nothing found Fix: Include section with "None identified in literature search"

5. No Synthesis

Bad: Long list of papers organized by theme Fix: Add biological model + testable hypotheses

6. Monolithic Bibliography

Bad: 200 papers embedded in report narrative Fix: Top 20-50 in report; full list in JSON/CSV

7. Silent Failures

Bad: "Expression data: [blank]" (tool failed, user doesn't know) Fix: "Expression data unavailable (API timeout); see HPA directly"

8. Wrong Tool Parameters (NEW)

Bad: Reactome_map_uniprot_to_pathways(uniprot_id=...) returns empty Fix: Verify params via get_tool_info(); use correct param id

9. Missing Versioned IDs (NEW)

Bad: GTEx returns empty for ENSG00000123456 Fix: Try versioned ID ENSG00000123456.12; document which worked

10. No Foundation Layer (NEW)

Bad: Query 15 specialized tools independently, miss data when some fail Fix: Query comprehensive aggregator (e.g., Open Targets) first

11. Scattered "No Data" Notes (NEW)

Bad: "No data" in 5 different sections; user doesn't know overall gaps Fix: Aggregate all gaps in dedicated Data Gaps section with recommendations

12. Aspirational Completeness (NEW)

Bad: "Include PPIs" ✓ (but only 3 interactors listed) Fix: "≥20 PPIs OR explanation why fewer"

13. Untested Tool Calls (CRITICAL - NEW)

Bad: Skill created with excellent documentation but tools never actually called Example: Documentation shows drugbank_get_drug_basic_info(drug_name_or_drugbank_id="...") but parameter doesn't exist Impact: All 4 broken skills discovered in 2026-02 had this issue - 0% functionality despite 1,500+ line docs

Fix: Test-driven skill development:

1. Write test script FIRST: test_[skill].py
2. Call every tool with real ToolUniverse instance
3. Verify parameters work and results are correct
4. Create working pipeline from tested code
5. Write documentation from working examples

Verification:

# Test every tool before documenting
def test_tools():
    tu = ToolUniverse()
    tu.load_tools()

    # Test Tool 1
    result = tu.tools.TOOL_NAME(param="value")
    assert result.get('status') == 'success', "Tool 1 failed"

    # Test Tool 2
    result = tu.tools.TOOL_NAME2(param="value")
    assert result.get('status') == 'success', "Tool 2 failed"

Rule: NEVER write skill documentation without first testing all tool calls.

---

NEW: Implementation-Agnostic Skills (2026-02 Update)

Critical Lesson from Real Fixes

All 4 broken skills (Drug-Drug Interaction, Clinical Trial Design, Antibody Engineering, CRISPR Screen Analysis) had excellent documentation but were never tested with real tool calls. This section documents critical lessons learned from fixing them.

14. Implementation-Agnostic Documentation

Problem: Skills written with implementation-specific code (Python SDK only) limit users to one interface. Users may access ToolUniverse via Python SDK, MCP (Model Context Protocol), or future APIs.

Solution: Separate general concepts from implementation details.

File Structure:

skills/[skill-name]/
├── SKILL.md                     # General workflow (NO Python/MCP code)
├── python_implementation.py     # Python SDK implementation
├── QUICK_START.md              # Multi-implementation examples
└── test_[skill].py             # Test script

SKILL.md Format (General):

## Phase 1: [Name]

**Objective**: What this phase achieves

**Tools needed**:
- Tool_A: Purpose and what it does
  - Input: parameter descriptions
  - Output: expected results

**Workflow**:
1. Query Tool_A with [inputs]
2. Extract [specific data]
3. If no results → try Tool_B
4. Continue with available data

**Decision logic**:
- When to use exact match vs fuzzy
- How to handle empty results
- When to trigger fallback

Don't include in SKILL.md:

• ❌ from tooluniverse import ToolUniverse
• ❌ tu.tools.TOOL_NAME(...)
• ❌ Python-specific code
• ❌ MCP-specific JSON

QUICK_START.md Format (Multi-Implementation):

## Choose Your Implementation

### Python SDK
[Python code examples]

### MCP (Model Context Protocol)
[Conversational prompts + JSON tool calls]

## Tool Parameters (All Implementations)
[Parameter table noting: applies to both Python SDK and MCP]

Why this matters: Users can choose Python SDK, MCP, or future interfaces without relearning the skill workflow.

15. SOAP Tools Special Handling

Problem: SOAP-based tools (IMGT, SAbDab, TheraSAbDab) require a special operation parameter that isn't obvious from function names. Missing this causes 100% tool failure.

Detection: If tool returns error "Parameter validation failed: 'operation' is a required property" → SOAP tool

Add to Tool Interface Verification (Section 1):

Tool Family	Parameter	CRITICAL Requirement
IMGT_*	operation	MUST be first parameter (e.g., "search_genes")
SAbDab_*	operation	MUST be first parameter (e.g., "search_structures")
TheraSAbDab_*	operation	MUST be first parameter (e.g., "search_by_target")

Example:

### Tool: IMGT_search_genes

**Parameters** (implementation-agnostic):
- `operation` (string, required): SOAP method name = "search_genes"
- `gene_type` (string, required): "IGHV", "IGKV", "IGLV"
- `species` (string, required): "Homo sapiens" for human

**Python SDK**:
```python
result = tu.tools.IMGT_search_genes(
    operation="search_genes",  # Required!
    gene_type="IGHV",
    species="Homo sapiens"
)

MCP:

{
  "operation": "search_genes",
  "gene_type": "IGHV",
  "species": "Homo sapiens"
}

Critical: SOAP tools will fail without operation parameter in both implementations.

### 16. Fallback Strategies for API Failures

**Problem**: Primary APIs can go down completely (e.g., DepMap 404 errors). Skills without fallbacks become 0% functional.

**Solution**: Implement tiered fallback strategies and document them clearly.

**Fallback Pattern**:
```markdown
## Fallback Strategy

**Primary**: [Best data source with detailed info]
**Fallback**: [Alternative source with partial data]
**Default**: [Continue with limited/unvalidated data]

**Python SDK**:
```python
try:
    result = tu.tools.PRIMARY_TOOL(param=value)
except:
    result = tu.tools.FALLBACK_TOOL(param=value)

MCP: Tell Claude to use Fallback if Primary unavailable

**Real Example from CRISPR Screen Analysis**:
- **Primary**: DepMap_search_genes (comprehensive essentiality data)
- **Fallback**: Pharos_get_target (TDL classification as essentiality proxy)
- **Default**: Continue with unvalidated genes

**Impact**: Skill went from 20% functional (total failure when DepMap down) to 60% functional (continues with Pharos data).

---

## Comprehensive Parameter Corrections (From Real Fixes)

**Add to Section 1 (Tool Interface Verification)**:

The following corrections were discovered while fixing 4 non-functional skills in February 2026:

| Tool | Common Mistake | Correct Parameter | Evidence |
|------|----------------|-------------------|----------|
| RxNorm_get_drug_names | `query` | `drug_name` | DDI skill fix |
| drugbank_get_drug_basic_info_by_drug_name_or_id | `drug_name_or_id` | `query` | DDI + Trial skill fixes |
| drugbank_get_pharmacology_by_drug_name_or_drugbank_id | `drug_name_or_drugbank_id` | `query` | Trial skill fix |
| drugbank_get_safety_by_drug_name_or_drugbank_id | `drug_name_or_drugbank_id` | `query` | Trial skill fix |
| FAERS_count_reactions_by_drug_event | `drug_name` | `medicinalproduct` | DDI skill fix |
| IMGT_search_genes | Missing parameter | `operation="search_genes"` | Antibody skill fix |
| IMGT_get_sequence | Missing parameter | `operation="get_sequence"` | Antibody skill fix |
| SAbDab_search_structures | Missing parameter | `operation="search_structures"` | Antibody skill fix |
| TheraSAbDab_search_by_target | Missing parameter | `operation="search_by_target"` | Antibody skill fix |

**Pattern**: Tool function names DO NOT predict parameter names - always test!

---

## Real-World Case Studies

### Case Study 1: Drug-Drug Interaction Skill

**Original State**: 0% functional
- Documentation showed `drugbank_get_drug_basic_info(drug_name_or_drugbank_id="...")`
- Tool actually requires `query` parameter
- Never tested with real ToolUniverse instance
- Beautiful 300+ line documentation, completely non-functional

**Fixed State**: 100% functional
- Created `test_ddi.py` - verified all tool parameters
- Created `python_implementation.py` - working 8-step pipeline
- Updated `QUICK_START.md` - both Python SDK and MCP examples
- Tool parameter table documents correct names

**Key Fixes**:
```markdown
| Tool | WRONG (in docs) | CORRECT (tested) |
|------|-----------------|------------------|
| RxNorm_get_drug_names | query | drug_name |
| drugbank_* | drug_name_or_id | query |
| FAERS_count_reactions | drug_name | medicinalproduct |

Lesson: Function names are misleading - get_drug_basic_info_by_drug_name_or_id actually takes query, not drug_name_or_id.

Case Study 2: Antibody Engineering Skill

Original State: 0% functional

• All SOAP tool calls missing operation parameter
• Error: "Parameter validation failed: 'operation' is a required property"
• 5/8 tools completely broken
• Documentation looked professional but untested

Fixed State: 80% functional

• Identified SOAP tools (IMGT, SAbDab, TheraSAbDab)
• Added operation parameter to all SOAP calls
• Created side-by-side Python/MCP examples
• Documented SOAP requirement prominently in QUICK_START

Key Fix:

## CRITICAL: SOAP Tools

**Python SDK**:
```python
tu.tools.IMGT_search_genes(
    operation="search_genes",  # Required!
    gene_type="IGHV"
)

MCP:

{
  "operation": "search_genes",
  "gene_type": "IGHV"
}

**Lesson**: SOAP tools have special requirements not obvious from function signatures. Always test.

### Case Study 3: CRISPR Screen Analysis Skill

**Original State**: 20% functional
- Primary API (DepMap) completely down (404 errors from both Sanger and Broad)
- No fallback strategy
- Skill failed completely when DepMap unavailable
- Users got zero results despite many alternative tools available

**Fixed State**: 60% functional
- Implemented Pharos TDL fallback for gene validation
- Documented fallback strategy in both Python SDK and MCP
- TDL classification (Tclin/Tchem/Tbio/Tdark) as essentiality proxy
- Skill continues with alternative data source

**Key Fix**:
```markdown

---

> **Extended Reference**: For detailed tool tables, examples, and templates, read `REFERENCE.md` in this skill directory.
> The agent can access it via: `read skills/devtu-optimize-skills/REFERENCE.md`