tachograph
specialized knowledge for parsing/marshalling EU tachograph files. Use when needing to understand the .DDD/.V1B file format, TLV/TV protocols, ASN.1 mappings, or EU regulation compliance.
Best use case
tachograph is best used when you need a repeatable AI agent workflow instead of a one-off prompt.
specialized knowledge for parsing/marshalling EU tachograph files. Use when needing to understand the .DDD/.V1B file format, TLV/TV protocols, ASN.1 mappings, or EU regulation compliance.
Teams using tachograph should expect a more consistent output, faster repeated execution, less prompt rewriting.
When to use this skill
- You want a reusable workflow that can be run more than once with consistent structure.
When not to use this skill
- You only need a quick one-off answer and do not need a reusable workflow.
- You cannot install or maintain the underlying files, dependencies, or repository context.
Installation
Claude Code / Cursor / Codex
Manual Installation
- Download SKILL.md from GitHub
- Place it in
.claude/skills/tachograph/SKILL.mdinside your project - Restart your AI agent — it will auto-discover the skill
How tachograph Compares
| Feature / Agent | tachograph | Standard Approach |
|---|---|---|
| Platform Support | Not specified | Limited / Varies |
| Context Awareness | High | Baseline |
| Installation Complexity | Unknown | N/A |
Frequently Asked Questions
What does this skill do?
specialized knowledge for parsing/marshalling EU tachograph files. Use when needing to understand the .DDD/.V1B file format, TLV/TV protocols, ASN.1 mappings, or EU regulation compliance.
Where can I find the source code?
You can find the source code on GitHub using the link provided at the top of the page.
SKILL.md Source
# EU Tachograph Domain Knowledge
This skill provides the domain expertise required to work with EU Tachograph files (Driver Card & Vehicle Unit).
## Core Concepts
- **Regulation First**: All implementation must derive directly from EU regulations (Data Dictionary).
- **Binary Fidelity**: Support perfect round-trip parsing/marshalling (byte-for-byte exactness).
- **Type Safety**: Use specific types for specific generations/formats.
## Workflows
### 1. Card File Structure (TLV)
- **Architecture**: See [card_structure.md](references/card_structure.md) for TLV, DF/EF structure, and signature handling.
- **Pattern**: Use a "Two-Pass" parsing strategy (Raw TLV -> Semantic Structure).
### 2. Regulation & ASN.1
- **Regulation**: Consult [regulation.md](references/regulation.md) to locate specific chapters (Data Dictionary is critical).
- **Definitions**: Use ASN.1 definitions from the regulation as the source of truth for all data types.
### 3. Generations & Versions
- **Details**: See [versions.md](references/versions.md) for a comprehensive overview of:
- **Generation 1**: Legacy (SHA-1, RSA-1024).
- **Generation 2 V1**: Smart Tachograph (SHA-256, ECC).
- **Generation 2 V2**: Smart Tachograph with GNSS/OSNMA support.
- **Protocol Matrix**: TLV (Card) vs TV (VU) tag ranges and structures.
- **Detection**: Use tag-based detection logic for both Card and VU files.
## Best Practices for Implementation
### Data Parsing
1. **ASN.1 Compliance**: Every parser function should reference the ASN.1 definition from the spec.
2. **No Magic Numbers**: Define constants for all binary offsets and lengths.
3. **Exact Lengths**: Validate fixed-structure lengths exactly (`==`), not loosely (`>=`).
4. **Nil Handling**: The protocol has no concept of "null", only "default values" (e.g., spaces for strings, 0 for numbers). Parsing functions should handle missing or zero-length input safely.
### Data Modeling
1. **Integers**: Use signed integers (`int32`/`int64`) for general numbers; the protocol rarely uses unsigned types in a way that maps cleanly to `uint` in all languages.
2. **Bitflags**: Prefer boolean fields over integer bitmasks for clarity.
3. **Signatures**: Model signed EFs by including a signature field (unless Regulation forbids).Related Skills
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