Agent profiles: accept Claude-style `tools:` scalar list with name aliases for cross-CLI plugins

[dfrysinger]

Summary

Allow custom agent profiles (in plugins and project-level .github/agents/) to declare their tool restrictions using Claude Code's scalar form in addition to the existing Copilot JSON-array form, and translate Claude tool names to Copilot equivalents via a fixed alias table.

Motivation

Custom agent profiles are commonly cross-ported between Claude Code and Copilot CLI. Plugin authors who maintain a single source of truth hit two problems:

1. Frontmatter shape mismatch. Claude accepts a comma-separated scalar (tools: Read, Write, Bash); Copilot accepts a JSON array (tools: ["view", "edit", "bash"]). When a Claude-authored agent installs into Copilot, the parser tolerates the unknown scalar but the restriction is not applied — the agent silently runs with unrestricted tool access. This is a quiet downgrade of the structural sandboxing the author intended.

2. Tool name divergence. Claude uses PascalCase names (Read, Write, Edit, Bash, Grep, Glob, WebFetch, Task). Copilot uses snake_case (view, edit, create, bash, grep, glob, web_fetch, task). The semantic mapping is unambiguous in practice but unknown to a generic parser.

A small upstream change would let one set of source files preserve restriction semantics in both CLIs without per-plugin build tooling.

Proposal

Extend the agent-profile parser:

1. Accept tools: as either a YAML sequence (current behavior) or a comma-separated scalar (Claude form).
2. When parsing names, apply a fixed alias map and translate to the Copilot canonical name:

Claude name	Copilot name(s)
Read	view
Write	create, edit
Edit	edit
Bash	bash
Grep	grep
Glob	glob
WebFetch	web_fetch
Task	task

3. Unknown names continue to warn (or fail in strict mode); they are not silently dropped.

Design notes

• Additive and backwards compatible. Existing Copilot-native agents are unaffected.
• The alias map is data, not policy. New tools can be added to the table without code changes.
• Write maps to two tools because Claude's Write covers both "create new" and "overwrite existing," whereas Copilot splits these into create and edit. Mapping to both preserves Claude semantics; authors who want narrower scope can switch to Copilot-canonical names.

Out of scope

• No changes to how tools: restrictions are enforced at runtime. The gain is purely from getting the restriction applied at all when the source is Claude-form.

Acceptance

• An agent file declaring tools: Read, Grep, Glob is restricted at runtime to view, grep, glob.
• An agent file declaring tools: ["view", "grep", "glob"] behaves identically to today.
• An unknown name (e.g., tools: Frobnicate) produces a clear warning (or strict-mode failure).

[dfrysinger]

Closing as not-actionable: the premise of this issue turned out to be wrong.

A live install probe of qrspi-plus (a Claude Code plugin with 41 agents using the scalar tools: form throughout) loaded 41/41 agents under Copilot CLI 1.0.55 without any transformation, once three unrelated malformed-YAML frontmatter bugs were fixed. See PR #193 for the probe results and the cross-CLI compatibility table.

So in practice Copilot CLI already accepts the Claude-style scalar tools: form. No alias layer needed. Apologies for the noise.