feat: add gpt-4.1 builtin model alias

[Copilot]

The GPT-4.1 model family (gpt-4.1, gpt-4.1-mini, gpt-4.1-nano and their dated variants) is live on OpenAI but had no builtin alias. The reasoning-model alias proposed in the inventory issue is deferred per reviewer request.

Changes

• pkg/workflow/model_aliases.go — New "gpt-4.1" entry in BuiltinModelAliases() with copilot/gpt-4.1* / openai/gpt-4.1* patterns; doc comment updated
• pkg/workflow/model_aliases_test.go — gpt-4.1 added to expectedFamilies and vendorFamilies coverage checks
• docs/.../model-alias-specification.md — New row in the §9.1 vendor family alias table

models:
  gpt-4.1:
    - "copilot/gpt-4.1*"
    - "openai/gpt-4.1*"

[pelikhan]

@copilot move models information to self contained JSON file embedded in go compiler.

[github-actions]

🧪 Test Quality Sentinel Report

Test Quality Score: 100/100

✅ Excellent test quality

Metric	Value
New/modified tests analyzed	1
✅ Design tests (behavioral contracts)	1 (100%)
⚠️ Implementation tests (low value)	0 (0%)
Tests with error/edge cases	1 (100%)
Duplicate test clusters	0
Test inflation detected	No
🚨 Coding-guideline violations	None

---

Test Classification Details

Test	File	Classification	Issues Detected
TestBuiltinModelAliases	pkg/workflow/model_aliases_test.go	✅ Design	None

---

Analysis

The PR adds gpt-4.1 to the builtin model alias map in model_aliases.go (+5 lines) and extends TestBuiltinModelAliases to verify the new alias is present and carries a copilot/* pattern (+2 lines). The test file already had a mandatory //go:build !integration build tag, uses no mock libraries, and all assertions include descriptive messages.

Test inflation ratio: 0.4:1 (2 test lines added vs 5 production lines added) — well within the 2:1 threshold.

Edge case coverage: TestBuiltinModelAliases also verifies the fresh-copy invariant (mutating the returned map does not pollute a subsequent call), which qualifies as an edge case scenario.

---

Verdict

✅ Check passed. 0% of modified tests are implementation tests (threshold: 30%).

---

📖 Understanding Test Classifications

Design Tests (High Value) verify what the system does:

• Assert on observable outputs, return values, or state changes
• Cover error paths and boundary conditions
• Would catch a behavioral regression if deleted
• Remain valid even after internal refactoring

Implementation Tests (Low Value) verify how the system does it:

• Assert on internal function calls (mocking internals)
• Only test the happy path with typical inputs
• Break during legitimate refactoring even when behavior is correct
• Give false assurance: they pass even when the system is wrong

---

Language Support

Tests analyzed:

• 🐹 Go (*_test.go): 1 modified test — unit (//go:build !integration)

---

References: §25290024934

🧪 Test quality analysis by Test Quality Sentinel · ● 509.7K · ◷

[github-actions]

✅ Test Quality Sentinel: 100/100. Test quality is excellent — 0% of modified tests are implementation tests (threshold: 30%).

[Copilot]

Pull request overview

Adds a new builtin gpt-4.1 model alias so workflows can reference the GPT-4.1 family through the shared alias map and documented specification.

Changes:

• Added a new gpt-4.1 builtin alias with Copilot/OpenAI wildcard patterns in the workflow model alias map.
• Extended the builtin-alias test lists to include gpt-4.1.
• Updated the model alias specification table to document the new vendor-family alias.

Show a summary per file

File	Description
pkg/workflow/model_aliases.go	Introduces the new builtin gpt-4.1 alias entry and updates the function doc comment.
pkg/workflow/model_aliases_test.go	Expands alias presence/coverage checks to include gpt-4.1.
docs/src/content/docs/reference/model-alias-specification.md	Documents gpt-4.1 in the builtin vendor-family alias table.

Copilot's findings

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• Files reviewed: 3/3 changed files
• Comments generated: 3