Read and fork GitHub Copilot CLI sessions

README.md

@@ -12,7 +12,7 @@
 
 Use it whenever you don't want to explain the whole job again — you hit an agent's usage limit, switch tools mid-task, pick up older work, or want a clean record of what happened.
 
-Works with **Claude Code**, **Codex**, **Cursor**, **Cline**, **Kimi**, **Antigravity**, **OpenCode**, **Pi Agent**, **ZCode**, and **DeepSeek Harness**.
+Works with **Claude Code**, **Codex**, **Copilot CLI**, **Cursor**, **Cline**, **Kimi**, **Antigravity**, **OpenCode**, **Pi Agent**, **ZCode**, and **DeepSeek Harness**.
 
 <div align="center">
 
@@ -54,7 +54,7 @@ herdr plugin install wilbeibi/herdr-catchup
 
 ## Usage
 
-Agents: `claude` · `codex` · `cursor` · `cline` · `kimi` · `agy` (Antigravity) · `opencode` · `pi-agent`
+Agents: `claude` · `codex` · `copilot` · `cursor` · `cline` · `kimi` · `agy` (Antigravity) · `opencode` · `pi-agent` · `zcode` · `deepseek` (dsh)
 
 Omit `<agent>` and catchup uses whichever agent has the newest session in this directory. Inside a live session, that's usually the session you're in.
 

SKILL.md

@@ -1,6 +1,6 @@
 ---
 name: catchup
-description: Recovers prior coding-agent session context by running `catchup <agent> --since-compact`, which extracts a clean summary of a previous Codex, Claude Code, Antigravity, Cline, Cursor, DeepSeek Harness, Kimi, OpenCode, Pi Agent, or ZCode session. Use when the user says "catch up", "what did the last session do", "get me up to speed", "I switched agents", or asks to recover/summarize a previous session before continuing. Do NOT use for the current conversation, git history, or any non-agent log.
+description: Recovers prior coding-agent session context by running `catchup <agent> --since-compact`, which extracts a clean summary of a previous Codex, Claude Code, Antigravity, Cline, Copilot CLI, Cursor, DeepSeek Harness, Kimi, OpenCode, Pi Agent, or ZCode session. Use when the user says "catch up", "what did the last session do", "get me up to speed", "I switched agents", or asks to recover/summarize a previous session before continuing. Do NOT use for the current conversation, git history, or any non-agent log.
 ---
 
 # catchup
@@ -24,7 +24,7 @@ catchup fork <agent>                    # native resume, full state
 catchup fork <agent> --into <other>     # seed a different agent with the transcript
 ```
 
-Agents: `codex`, `claude`, `agy` (Antigravity), `cline`, `cursor`, `deepseek` (dsh), `kimi`, `opencode`, `pi-agent`, `zcode`.
+Agents: `codex`, `claude`, `agy` (Antigravity), `cline`, `copilot`, `cursor`, `deepseek` (dsh), `kimi`, `opencode`, `pi-agent`, `zcode`.
 
 ## Operation
 

internal/cli/cli.go

@@ -25,6 +25,7 @@ import (
 	"github.com/wilbeibi/catchup/internal/claude"
 	"github.com/wilbeibi/catchup/internal/cline"
 	"github.com/wilbeibi/catchup/internal/codex"
+	"github.com/wilbeibi/catchup/internal/copilot"
 	"github.com/wilbeibi/catchup/internal/cursor"
 	"github.com/wilbeibi/catchup/internal/deepseek"
 	"github.com/wilbeibi/catchup/internal/kimi"
@@ -40,7 +41,8 @@ const helpText = `Usage: catchup [agent[/<rank>]] [flags]        read a past ses
        catchup fork --into <agent> --from <file | - | url>
        catchup install-skill [agent]
 
-Agents: codex, claude, agy (Antigravity), cline, cursor, deepseek (dsh), kimi, opencode, pi-agent, zcode
+Agents: codex, claude, agy (Antigravity), cline, copilot, cursor, deepseek (dsh),
+kimi, opencode, pi-agent, zcode
 Omit the agent to use whichever has the newest session here. Bare ` + "`catchup`" + `
 prints that session in full, as Markdown. The flags refine three things:
 which session, how much of it, and as what.
@@ -317,6 +319,7 @@ func providerNames() []string {
 		session.ProviderClaude,
 		session.ProviderAgy,
 		session.ProviderCline,
+		session.ProviderCopilot,
 		session.ProviderCursor,
 		session.ProviderDeepSeek,
 		session.ProviderKimi,
@@ -338,6 +341,8 @@ func selectProvider(name string) (session.Provider, error) {
 		return agy.New(), nil
 	case session.ProviderCline:
 		return cline.New(), nil
+	case session.ProviderCopilot:
+		return copilot.New(), nil
 	case session.ProviderCursor:
 		return cursor.New(), nil
 	case session.ProviderDeepSeek:
@@ -363,7 +368,7 @@ func selectProvider(name string) (session.Provider, error) {
 		if name == "dsh" {
 			return nil, fmt.Errorf(`unknown agent "dsh"; DeepSeek Harness's agent name is deepseek`)
 		}
-		return nil, fmt.Errorf("unknown agent %q (want codex, claude, agy, cline, cursor, deepseek, kimi, opencode, pi-agent, or zcode); run catchup --help", name)
+		return nil, fmt.Errorf("unknown agent %q (want codex, claude, agy, cline, copilot, cursor, deepseek, kimi, opencode, pi-agent, or zcode); run catchup --help", name)
 	}
 }
 
@@ -805,6 +810,10 @@ func intoCommand(target, prompt, model string) (string, []string, error) {
 		return "cline", append(modelArgs("--model", model), "-i", prompt), nil
 	case session.ProviderCursor:
 		return "cursor-agent", append(modelArgs("--model", model), prompt), nil
+	case session.ProviderCopilot:
+		// -i starts interactive and auto-executes the prompt; a bare -p is
+		// non-interactive and exits when the answer lands.
+		return "copilot", append(modelArgs("--model", model), "-i", prompt), nil
 	case session.ProviderKimi:
 		// Kimi rejects positional arguments and its -p flag is
 		// non-interactive print mode, so there is no way to start an
@@ -896,6 +905,13 @@ func forkCommand(src session.Source, model string) (string, []string, error) {
 		// Cline has no fork, and a bare --id only prints a session summary
 		// and exits; -i opens the TUI resumed on the session.
 		return "cline", append([]string{"-i", "--id", src.Ref.SessionID}, modelArgs("--model", model)...), nil
+	case session.ProviderCopilot:
+		if src.Ref.SessionID == "" {
+			return "", nil, fmt.Errorf("fork copilot: missing session id")
+		}
+		// Copilot has no fork; --resume is its native resume, and it takes
+		// the id inline (a bare --resume opens the session picker).
+		return "copilot", append([]string{"--resume=" + src.Ref.SessionID}, modelArgs("--model", model)...), nil
 	case session.ProviderCursor:
 		if src.Ref.SessionID == "" {
 			return "", nil, fmt.Errorf("fork cursor: missing session id")

internal/cli/cli_test.go

@@ -490,6 +490,10 @@ func TestForkCommand(t *testing.T) {
 		{"opencode", session.Source{Ref: session.Ref{Provider: session.ProviderOpenCode, SessionID: "o1"}}, "", "opencode --session o1 --fork"},
 		{"pi path", session.Source{Ref: session.Ref{Provider: session.ProviderPiAgent, SessionID: "p1"}, Path: "/tmp/pi.jsonl"}, "", "pi --fork /tmp/pi.jsonl"},
 		{"codex with model", session.Source{Ref: session.Ref{Provider: session.ProviderCodex, SessionID: "c1"}}, "gpt-5.6", "codex fork c1 -m gpt-5.6"},
+		// The id is inline: a bare --resume opens Copilot's session picker,
+		// which would swallow a separated id as an unrelated argument.
+		{"copilot", session.Source{Ref: session.Ref{Provider: session.ProviderCopilot, SessionID: "gh1"}}, "", "copilot --resume=gh1"},
+		{"copilot with model", session.Source{Ref: session.Ref{Provider: session.ProviderCopilot, SessionID: "gh1"}}, "gpt-5.4", "copilot --resume=gh1 --model gpt-5.4"},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -715,6 +719,7 @@ func TestIntoCommandModelPlacement(t *testing.T) {
 		{session.ProviderClaude, "--model M PROMPT"},
 		{session.ProviderAgy, "--model M -i PROMPT"},
 		{session.ProviderOpenCode, "--model M --prompt PROMPT"},
+		{session.ProviderCopilot, "--model M -i PROMPT"},
 	}
 	for _, tt := range tests {
 		t.Run(tt.target, func(t *testing.T) {