Agent skill

Schema Mapper

by nimrodfisher in nimrodfisher/data-analytics-skills

Document column-level mappings between source and target schemas.

MITAuto-check passedData & Analytics

Install Schema Mapper

skills CLI
$ npx skills add nimrodfisher/data-analytics-skills --skill schema-mapper -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install nimrodfisher/data-analytics-skills schema-mapper --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/nimrodfisher/data-analytics-skills.git skills-src && mkdir -p .claude/skills && cp -r skills-src/02-documentation-knowledge/schema-mapper .claude/skills/schema-mapper && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
schema-mapper
GitHub stars
465
Token cost
~614 tokens
SKILL.md length
306 words
Files
4 (incl. scripts, references, assets)
Skills in repo
31
Repo updated
First seen
Licence
MIT

At a glance

Document column-level mappings between source and target schemas.

  • Works in 6 steps: Collect the source schema — list every… → Collect the target schema — same… → Map source columns to target columns —… → …
  • Integrating data from multiple systems
  • Runs Python scripts from its folder
  • Designing ETL transformations

What it does

Schema Mapper is an agent skill from nimrodfisher/data-analytics-skills. Document column-level mappings between source and target schemas. Use when integrating data from multiple systems, designing ETL transformations, or documenting how raw fields become analytical assets.

Its SKILL.md is about 610 tokens, which your agent loads only when the skill is triggered. The skill folder holds 6 other files, including scripts, reference files and assets (for example `assets/schema_mapping_template.md`, `references/schema_mapping_patterns.md` and `scripts/schema_compare.py`).

It sits in Data & Analytics, covering Data pipelines and ETL. The repository describes itself as: A comprehensive list of Claude & Codex skills for a wide range of data analytics tasks. The licence is MIT.

When your agent uses it

  • Integrating data from multiple systems
  • Designing ETL transformations
  • Documenting how raw fields become analytical assets

Example prompts

  • “/schema-mapper”

Requirements

  • Python 3

Workflow steps

6 steps, taken from the first numbered list in SKILL.md.

  1. Collect the source schema — list every column name, data type, nullable flag, and a brief description. Pull from INFORMATION_SCHEMA, a…
  2. Collect the target schema — same structure for the destination table or model. If the target doesn't exist yet, draft it based on the…
  3. Map source columns to target columns — for each target column, identify the source column(s) that feed it. Record direct mappings (rename…
  4. Document transformation rules — for each derived mapping, write the exact transformation (e.g., CAST(amount_cents AS FLOAT) / 100.0…
  5. Flag gaps — identify target columns with no source (need to be created or defaulted) and source columns with no target (dropped or…
  6. Produce the mapping document — complete assets/schema_mapping_template.md with the full column inventory and share for review before…

What it can do on your machine

Read from SKILL.md and the folder at commit 9449d36. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    Ships 1 file in scripts/ (Python), which the agent can run.

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    No URLs in SKILL.md.

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names no API keys, tokens, secrets or passwords.

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Schema Mapper loads about 614 tokens when it runs, and up to ~1.2k if it reads all its reference files. Until then it costs about 54 tokens; SKILL.md has 306 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~54
When it runs · the whole SKILL.md, loaded when a task matches
~614
With references · SKILL.md plus every file in references/, read only if the agent opens them
~1.2k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); the scripts in this folder are not scanned.

SKILL.md

The full file from nimrodfisher/data-analytics-skills at commit 9449d36, republished under its MIT licence (© nimrodfisher). 306 words, ~614 tokens.

Download SKILL.mdSave it as .claude/skills/schema-mapper/SKILL.md (or your agent's skills folder). This skill also uses 3 other files; get the full folder from GitHub.
name
schema-mapper
description
Document column-level mappings between source and target schemas. Use when integrating data from multiple systems, designing ETL transformations, or documenting how raw fields become analytical assets.

Schema Mapper

When to use

  • Integrating a new data source and need to map its fields to the existing data model
  • Designing an ETL or dbt transformation and need to document the logic
  • Auditing what happened to a field during a migration
  • Onboarding a new analyst who needs to understand where columns come from
  • Preparing a data catalog entry that requires lineage at the column level

Process

  1. Collect the source schema — list every column name, data type, nullable flag, and a brief description. Pull from INFORMATION_SCHEMA, a data dictionary, or the source API documentation.
  2. Collect the target schema — same structure for the destination table or model. If the target doesn't exist yet, draft it based on the analytical requirements.
  3. Map source columns to target columns — for each target column, identify the source column(s) that feed it. Record direct mappings (rename only) and derived mappings (calculation, type cast, lookup join). Use scripts/schema_compare.py to automate direct-name matches.
  4. Document transformation rules — for each derived mapping, write the exact transformation (e.g., CAST(amount_cents AS FLOAT) / 100.0, COALESCE(first_name, email)).
  5. Flag gaps — identify target columns with no source (need to be created or defaulted) and source columns with no target (dropped or deferred). Record a decision for each.
  6. Produce the mapping document — complete assets/schema_mapping_template.md with the full column inventory and share for review before implementation.

Inputs the skill needs

  • Source schema: table name, column names, data types, and descriptions
  • Target schema: same, or the analytical requirements that define it
  • Any existing transformation logic (SQL, dbt models, Python code)
  • Business rules that govern how values should be transformed or defaulted
  • Stakeholder who can resolve ambiguous fields

Output

  • scripts/schema_compare.py — compares two schemas and finds direct-name matches and type mismatches
  • assets/schema_mapping_template.md — completed column-by-column mapping with transformation rules, gaps, and decisions
  • Optional: transformation SQL or dbt YAML generated from the mapping

© nimrodfisher, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 3 other files (scripts, references, assets) in 02-documentation-knowledge/schema-mapper of nimrodfisher/data-analytics-skills.

  • SKILL.md
  • assets/schema_mapping_template.md
  • references/schema_mapping_patterns.md
  • scripts/schema_compare.py

Open the folder on GitHubat commit 9449d36

Compare with similar skills

Schema Mapper next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Schema Mapper compared with similar skills
SkillStarsUsed inTokensAuto-checkLicenceRepo updated
Schema Mapper this skillnimrodfisher/data-analytics-skills465—~614Automated safety check: PassMIT
Crawl4AI Web Scrapingsmallnest/goclaw5981 repos~2.5kAutomated safety check: PassMIT
Glue 09 10 Migrationaws-samples/aws-glue-samples1.5k—~2.4kAutomated safety check: PassMIT-0
Migrate Glue Devendpoint To Interactive Sessionsaws-samples/aws-glue-samples1.5k—~3.6kAutomated safety check: PassMIT-0
Dbt Databricks PR Readydatabricks/dbt-databricks380—~2.8kAutomated safety check: PassApache-2.0
Mz Dbt ReleaseMaterializeInc/materialize6.4k—~1.2kAutomated safety check: PassCustom licence

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Questions about Schema Mapper

What does Schema Mapper do?

Document column-level mappings between source and target schemas. Schema Mapper is an agent skill from nimrodfisher/data-analytics-skills. Document column-level mappings between source and target schemas.

When should I use Schema Mapper?

Schema Mapper fits situations like: integrating data from multiple systems; designing ETL transformations; documenting how raw fields become analytical assets.

How do I install Schema Mapper in Claude Code?

Run `npx skills add nimrodfisher/data-analytics-skills --skill schema-mapper -a claude-code`. Or copy the skill folder (02-documentation-knowledge/schema-mapper in nimrodfisher/data-analytics-skills) into .claude/skills/schema-mapper in your project. Claude Code loads it when a task matches its description.

How do I install Schema Mapper in Codex?

Run `npx skills add nimrodfisher/data-analytics-skills --skill schema-mapper -a codex`. Or copy the skill folder (02-documentation-knowledge/schema-mapper in nimrodfisher/data-analytics-skills) into .agents/skills/schema-mapper in your project. Codex loads it when a task matches its description.

Can I use Schema Mapper in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add nimrodfisher/data-analytics-skills --skill schema-mapper -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/schema-mapper, .gemini/skills/schema-mapper, .github/skills/schema-mapper and .opencode/skills/schema-mapper in your project.

What does Schema Mapper need to run?

Going by SKILL.md and its folder, Schema Mapper needs Python for the scripts in its folder. Our summary lists: Python 3.

Does Schema Mapper access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Schema Mapper safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. The check reads SKILL.md only: the scripts in the folder are not scanned, so read them before running anything.

What licence does Schema Mapper use?

Schema Mapper is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Schema Mapper use?

About 614 tokens (SKILL.md is roughly 2.5k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 613 tokens, read only when the agent opens those files.

What are the alternatives to Schema Mapper?

Skills that share tags, products or a category with Schema Mapper: Crawl4AI Web Scraping (smallnest/goclaw, 598 stars), Glue 09 10 Migration (aws-samples/aws-glue-samples, 1.5k stars), Migrate Glue Devendpoint To Interactive Sessions (aws-samples/aws-glue-samples, 1.5k stars) and Dbt Databricks PR Ready (databricks/dbt-databricks, 380 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Schema Mapper?

nimrodfisher (a GitHub user) maintains it in nimrodfisher/data-analytics-skills, which has 465 GitHub stars. The repository holds 31 skills in this directory. The repository was last updated on September 25, 2026.

Source: nimrodfisher/data-analytics-skills on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.