Rework agent code review guidance

[Edward Chen (edgchen1)]

Description

Try to organize agent guidance so it is more extensible. E.g., add path-specific instructions, code review skill.

Also moved skills to .github/skills. Added pointer to this location in AGENTS.md.

Motivation and Context

Goal is to improve agent code reviewing by providing guidance to follow.

[Hariharan Seshadri (hariharans29)]

Overall LGTM

[Copilot]

Pull request overview

Reorganizes agent guidance into extensible repository-wide, path-scoped, and review-specific layers. No actionable findings found.

Changes:

• Adds guidance for extending agent instructions.
• Introduces a code-review skill and C API-specific instructions.
• Simplifies GitHub Copilot instructions to reference canonical guidance.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
docs/Agent_Coding_Guidance.md	Documents guidance layers and extension practices.
AGENTS.md	Adds path-scoped review and comment guidance.
.github/instructions/c-api.instructions.md	Defines C API compatibility and versioning rules.
.github/copilot-instructions.md	Redirects GitHub Copilot to canonical instructions.
.agents/skills/code-review/SKILL.md	Adds the standard diff-review workflow.

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.

[Copilot]

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated no new comments.

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated no new comments.

Suppressed comments (1)

.github/skills/code-review/SKILL.md:3

• Both .github/skills/ and .agents/skills/ are Copilot skill discovery roots, so this introduces two skills with the same code-review name and description. Duplicate skills are indexed independently with no defined precedence; Copilot may expose/load both or activate this forwarding stub instead of the canonical workflow. Keep a single discoverable skill (the canonical .agents/skills/code-review/SKILL.md is already in a supported location) and remove this adapter.

name: code-review
description: "Review ONNX Runtime pull requests, branches, commits, patches, and working-tree changes for actionable findings and missing tests."

[Copilot]

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated no new comments.

Suppressed comments (3)

docs/Agent_Coding_Guidance.md:14

• The “Guidance Layers” table omits the .github/skills/ compatibility layer that this PR introduces. Since .github/skills/README.md states it’s needed for GitHub.com Copilot skill activation, listing it here will prevent maintainers from overlooking or removing it as “non-canonical”.

| Location | Purpose |
|---|---|
| [`AGENTS.md`](../AGENTS.md) | Repository-wide guidance. |
| [`.github/copilot-instructions.md`](../.github/copilot-instructions.md) | Thin GitHub Copilot adapter that points to canonical guidance. |
| [`.github/instructions/`](../.github/instructions/) | Guidance for agents working with specific paths. |
| [`.agents/skills/code-review/SKILL.md`](../.agents/skills/code-review/SKILL.md) | Generic diff-driven review workflow and finding format. |
| [`.agents/skills/`](../.agents/skills/) | Deeper workflows and knowledge for particular tasks or subsystems. |

.github/instructions/c-api.instructions.md:4

• The applyTo scope only matches the public headers, but this guidance explicitly references implementation updates in onnxruntime/core/session/onnxruntime_c_api.cc and related initializer .cc files. If a PR changes those .cc files without touching the headers, this instruction won’t load, reintroducing the exact review confusion this guidance is meant to prevent.

---
description: "C API implementation and review guidance for public C API updates."
applyTo: "include/onnxruntime/core/session/onnxruntime_c_api.h,include/onnxruntime/core/session/onnxruntime_ep_c_api.h"
---

.github/skills/code-review/SKILL.md:6

• The link text uses Windows-style backslashes (.agents\skills\...), which can render oddly in Markdown and makes it harder to copy/paste as a repo path. Using forward slashes in the displayed path keeps it consistent with the link target and other docs.

Read the canonical code-review skill file at [.agents\skills\code-review\SKILL.md](../../../.agents/skills/code-review/SKILL.md).

[Copilot]

Pull request overview

Copilot reviewed 5 out of 17 changed files in this pull request and generated no new comments.

Suppressed comments (1)

.github/instructions/c-api.instructions.md:4

• The applyTo scope only matches the C API headers, but the guidance here also targets the implementation sites that usually change alongside them (e.g., onnxruntime/core/session/onnxruntime_c_api.cc and plugin_ep/ep_api.cc). If an agent edits those .cc files without touching the headers, this instruction won’t be discovered, increasing the chance of incorrect version-table or ABI changes.

---
description: "C API implementation and review guidance for public C API updates."
applyTo: "include/onnxruntime/core/session/onnxruntime_c_api.h,include/onnxruntime/core/session/onnxruntime_ep_c_api.h"

[Copilot]

Pull request overview

Copilot reviewed 5 out of 17 changed files in this pull request and generated no new comments.

Suppressed comments (1)

.github/instructions/c-api.instructions.md:3

• applyTo only matches the public headers, but this guidance also covers the corresponding C API initializer/implementation files (e.g., appending to ort_api_1_to_N in onnxruntime_c_api.cc and updating companion API initializers). As written, edits to those .cc files without touching the headers won’t pick up these instructions; consider expanding applyTo to include the key implementation files so the guidance reliably applies to “C API implementation and review” changes.

applyTo: "include/onnxruntime/core/session/onnxruntime_c_api.h,include/onnxruntime/core/session/onnxruntime_ep_c_api.h"