---
name: datacontract-edit
description: Edit an output-port ODCS file under models/output_ports/v<N>/, run the contract test against the live data, and classify any failures as breaking or non-breaking changes — with suggested fixes. Only edits output-port contracts (the spec this data product commits to); input-port contracts under models/input_ports/ are upstream's responsibility and refreshed by dataproduct-implement. Trigger when the user asks to "add/remove/change a column in the data contract", "update the data contract", or "test contract changes".
---

# Edit a data contract and test the impact

Change an output-port `models/output_ports/v<N>/*.odcs.yaml` file, run the contract test, and tell the user whether the change breaks consumers.

This skill operates **only on output-port contracts** — the spec this data product commits to. Input-port contracts under `models/input_ports/` are cached snapshots of upstream's spec and are not editable here; if you want to refresh one (because upstream changed it), run `dataproduct-implement` instead.

## How to run this skill

> `${PLUGIN_ROOT}` below refers to the root of this plugin — the directory that contains `skills/`. On Claude Code it is set automatically as `${CLAUDE_PLUGIN_ROOT}` — use that. On any other agent (Codex, Copilot CLI, etc.) it is unset; resolve it as `../..` relative to **this `SKILL.md` file's directory** (i.e. the grandparent of `skills/<this-skill>/`).

### Plan announcement (before Step 0)

Before running Step 0, print this plan to the user verbatim:

> Running **datacontract-edit**. I'll:
> 1. Locate the output-port contract file under `models/output_ports/v<N>/` that matches your request.
> 2. Apply the edit in place and show you a unified diff.
> 3. Run `datacontract test` against the live server to check the change.
> 4. Classify each failure as breaking-schema, breaking-quality, additive, or unrelated.
> 5. Report and suggest concrete fixes (no version bump, no v2 directory, no dbt model changes).

Then proceed.

### Step 0 — Locate the contract

- Search only `models/output_ports/**/*.odcs.yaml` — never `models/input_ports/`. If the user names an input-port contract, stop and explain it can't be edited here (refresh via `dataproduct-implement` instead).
- If the user named a contract file or column, find the matching file under `models/output_ports/`.
- If multiple contracts exist and it's ambiguous, list them and ask which one.
- Read the file and remember the current `models` block as `BEFORE`.

### Step 1 — Apply the edit

Edit the ODCS YAML in place using the user's instruction. Keep the change minimal — do not reformat unrelated fields.

Common edits and the right shape:

| User says | What to change |
|---|---|
| "add column X" | Append a field under the relevant model with at least `type`; set `required: false` by default unless the user says it's required |
| "remove column X" | Delete the field; this is **breaking** — flag in Step 4 |
| "rename X to Y" | Rename the field; this is **breaking** — flag |
| "make X required" | Add `required: true`; **breaking** if existing rows can be null |
| "change X type from int to string" | Update `type`; **breaking** unless the new type is a strict superset (e.g. int → bigint) |
| "add a unique/not_null/enum check" | Add to the field's quality rules; breaking iff existing data violates the new rule — only Step 2 can tell |

After editing, remember the new `models` block as `AFTER` and show the user a unified diff before continuing.

### Step 2 — Run the contract test

Run the test with the **`datacontract` CLI** against the local contract file:

```
datacontract test models/output_ports/v<N>/<file>.odcs.yaml --server <server> --logs
```

- If the contract has more than one server, ask which one (typically `production`). Default to `all` only if the user explicitly asks.
- Use `--logs` so failure detail is in the output you read; otherwise the CLI only prints a summary.
- If the user wants the report persisted, add `--output ./test-results/junit.xml --output-format junit`.
- Capture stdout + exit code as `TEST_RESULT`. Non-zero exit means at least one rule failed; the log section names the failing field/rule.

Pre-reqs the CLI needs (verify before running, fail fast with a clear message if missing):

- `uv run --quiet datacontract --version` succeeds from the project root. If it fails, run `uv sync` and retry. Invoke as `uv run datacontract test …` for every CLI invocation in this skill.
- The chosen server's credentials available as env vars per the ODCS server block (e.g. `DATACONTRACT_SNOWFLAKE_USERNAME` / `..._PASSWORD`, or `DATACONTRACT_DATABRICKS_TOKEN`). Tell the user which env vars are missing — do not try to source them yourself.

Do **not** use the platform's server-side contract-test endpoint from this skill. The local `datacontract` CLI runs against the edited file and gives line-level failure detail; testing the published version on the server would test the *previous* contract, which defeats the point of testing the edit.

### Step 3 — Classify the outcome

Group every failure into one of these buckets:

| Bucket | Examples | Severity |
|---|---|---|
| **Breaking — schema** | column removed, type narrowed, column renamed | High — bump major version, deprecate old port |
| **Breaking — quality** | new `not_null`/`unique`/`enum` rule violated by existing data | High — clean data first, then re-test |
| **Non-breaking — additive** | new optional column, widened type, loosened rule | Low — minor version bump |
| **Test failure unrelated to the edit** | flaky source, infra error, unchanged rule failing | Investigate separately |

For each failure, name the exact field/rule and which bucket it falls into. Don't lump them together.

### Step 4 — Report and suggest fixes

End with this two-part recap. The `Status` column uses the shared enum (`created`, `updated`, `already present`, `deferred`, `skipped`), and below it a classification table covers any test failures.

**Part 1 — outcome table.**

| Artifact | Status | Details |
|---|---|---|
| Contract file | updated | `models/output_ports/v<N>/<file>.odcs.yaml` — show the unified diff inline |
| Contract test | … | `pass`, `fail (<N> failures)`, or `not run (missing creds)` — name the server |
| Breaking — schema | … | count of failures in this bucket, or "—" |
| Breaking — quality | … | count of failures in this bucket, or "—" |
| Non-breaking — additive | … | count of changes in this bucket, or "—" |
| Test failures unrelated to the edit | … | count, or "—" |
| Recommended version bump | … | `patch` / `minor` / `major` based on the edit |

For the four "bucket" rows, leave `Status = —` and put the failure count + a one-line bucket description in `Details`.

**Part 2 — next steps.** Per failure, give a concrete fix suggestion:

- **Schema breaking**: bump to a new output port version (`models/output_ports/v2/`), keep v1 alive, add a deprecation note in `<id>.odps.yaml`.
- **Quality breaking**: SQL snippet to find the offending rows so the user can decide whether to clean, accept, or relax the rule.
- **Additive**: bump the contract's `version` minor, no consumer impact.
- If no failures, recommend the version bump (patch for cosmetic, minor for additive, major for breaking even when the test happened to pass).

**Do not auto-bump the contract version, do not create v2/ directories, and do not modify dbt models.** Surface the recommendation; let the user decide.

## Constraints

- **Always run the test after every edit.** A passing edit looks the same as a breaking edit until you run it.
- **Don't edit the dbt models in this skill.** Changing the contract is a separate decision from changing the implementation. If the user wants both, run `dataproduct-implement` after this skill.
- **Don't fetch a remote version of the contract** — operate on the local file. If the user wants to pull the published version, ask them to do that explicitly first (it can be a one-line `entropy-data datacontracts get <id> -o yaml` redirected to the file).
- **Idempotent**: re-running with the same edit should be a no-op (same diff = empty, same test = same result).