feat: add at_filename usage for users to directly involve a filepath to context

README.md

@@ -53,6 +53,28 @@ mscli
 | `/model <provider:model>` | Switch LLM model |
 | `/clear` | Clear chat |
 
+### `@file` Input Expansion
+
+`ms-cli` supports inline file expansion for plain chat input and these text-tail commands:
+
+- `/report`
+- `/diagnose`
+- `/fix`
+- `/skill <name> ...`
+- direct skill aliases such as `/pdf ...`
+
+Use a standalone workspace-relative token like `@docs/bug.md` to inline a text file into the prompt.
+Use `@@name` to keep a literal `@name` token.
+
+v1 limits:
+
+- only standalone whitespace-delimited `@relative/path` tokens are expanded
+- paths with spaces are not supported
+- files must stay inside the current workspace
+- files must be UTF-8 text without NUL bytes
+- files larger than `64 KiB` are rejected
+- any invalid `@file` reference fails the whole input
+
 ### Server Setup
 
 The bug and project server runs separately:

docs/at-file-input-expansion-summary.md

@@ -0,0 +1,101 @@
+# `@file` Input Expansion Summary
+
+## Overview
+
+This change adds conservative `@file` prompt expansion support on branch
+`refactor-arch-4.11-support-at-file`.
+
+The goal is to let users reference workspace files in prompts without
+changing slash command recognition or disturbing structured command parsing.
+
+## Supported Surfaces
+
+`@relative/path` expansion is enabled for:
+
+- Plain chat input
+- `/report`
+- `/diagnose`
+- `/fix`
+- `/skill <name> ...`
+- Direct skill aliases such as `/pdf ...`
+
+It is intentionally not enabled for structured commands such as `/project`,
+`/train`, `/model`, `/permission`, `/login`, `/issues`, `/status`, `/bugs`,
+`/claim`, `/close`, or `/dock`.
+
+## Syntax and Safety Rules
+
+Version 1 behavior is intentionally strict:
+
+- Only standalone whitespace-delimited `@relative/path` tokens expand
+- `@@name` keeps a literal `@name`
+- Paths must remain inside the current workspace
+- Absolute paths and escaping paths are rejected
+- Directories and missing files are rejected
+- Any invalid `@file` reference fails the whole input
+
+Expanded file references are injected into prompts in this form:
+
+```text
+[file path="/absolute/workspace/path.txt"]
+```
+
+## Implementation Notes
+
+The change is split across three main areas:
+
+1. Shared file validation and file-path resolution
+
+- Added `internal/workspacefile/workspacefile.go`
+- Centralizes workspace-relative path validation
+- Reused by input expansion
+
+2. Input expansion and raw command parsing
+
+- Added `internal/app/input_expansion.go`
+- Keeps slash detection unchanged
+- Expands plain chat only after confirming input is not a slash command
+- Parses slash commands from raw input first, then expands only approved
+  command remainders
+
+3. Command-specific behavior preservation
+
+- `/diagnose` and `/fix` still use the first raw token to decide whether the
+  command targets `ISSUE-*`
+- In issue mode, only the remainder after the issue key is expanded
+- `/skill` and direct skill aliases now preserve the raw request tail so the
+  skill name itself is never changed by `@file`
+
+## Documentation Updates
+
+User-facing notes were added to:
+
+- `README.md`
+- `/help` output in `internal/app/commands.go`
+
+## Validation
+
+Targeted tests were added in `internal/app/input_expansion_test.go`.
+
+Validated scenarios include:
+
+- Plain chat path expansion
+- Multiple `@file` tokens
+- `@@` escaping
+- Excluded commands remaining unchanged
+- `/report`, `/diagnose`, `/fix`, `/skill`, and skill alias behavior
+- Issue-target preservation for `/diagnose` and `/fix`
+- Failure on missing, unsafe, or directory paths
+
+The targeted verification command that passed was:
+
+```powershell
+go test ./internal/app ./tools/fs -run "Test(ExpandInputText|ProcessInput|HandleCommand|CmdIssue|ParseIssueCommandTarget|InterruptTokenCancelsActiveTask)"
+```
+
+## Notes
+
+- Some broader Windows-specific tests in the repository already fail for
+  unrelated path/session reasons and were not changed as part of this work.
+- This implementation is intentionally conservative and leaves punctuation-
+  adjacent `@file` forms and paths with spaces for future expansion if needed.

internal/app/commands.go

@@ -12,14 +12,15 @@ import (
 )
 
 func (a *Application) handleCommand(input string) {
-	parts := strings.Fields(input)
-	if len(parts) == 0 {
+	cmd, ok := splitRawCommand(input)
+	if !ok {
 		return
 	}
+	args := strings.Fields(cmd.Remainder)
 
-	switch parts[0] {
+	switch cmd.Name {
 	case "/model":
-		a.cmdModel(parts[1:])
+		a.cmdModel(args)
 	case "/exit":
 		a.cmdExit()
 	case "/compact":
@@ -29,63 +30,128 @@ func (a *Application) handleCommand(input string) {
 	case "/test":
 		a.cmdTest()
 	case "/permission":
-		a.cmdPermission(parts[1:])
+		a.cmdPermission(args)
 	case "/yolo":
 		a.cmdYolo()
 	case "/train":
-		a.cmdTrain(parts[1:])
+		a.cmdTrain(args)
 	case "/project":
-		a.cmdProjectInput(strings.TrimSpace(strings.TrimPrefix(input, "/project")))
+		a.cmdProjectInput(cmd.Remainder)
 	case "/login":
-		a.cmdLogin(parts[1:])
+		a.cmdLogin(args)
 	case "/report":
-		a.cmdUnifiedReport(strings.TrimSpace(strings.TrimPrefix(input, "/report")))
+		expanded, err := a.expandReportInput(cmd.Remainder)
+		if err != nil {
+			a.emitInputExpansionError(err)
+			return
+		}
+		a.cmdUnifiedReport(expanded)
 	case "/issues":
-		a.cmdIssues(parts[1:])
+		a.cmdIssues(args)
 	case "/__issue_detail":
-		a.cmdIssueDetail(parts[1:])
+		a.cmdIssueDetail(args)
 	case "/__issue_note":
-		a.cmdIssueNoteInput(strings.TrimSpace(strings.TrimPrefix(input, "/__issue_note")))
+		a.cmdIssueNoteInput(cmd.Remainder)
 	case "/__issue_claim":
-		a.cmdIssueClaim(parts[1:])
+		a.cmdIssueClaim(args)
 	case "/status":
-		a.cmdIssueStatus(parts[1:])
+		a.cmdIssueStatus(args)
 	case "/diagnose":
-		a.cmdDiagnose(strings.TrimSpace(strings.TrimPrefix(input, "/diagnose")))
+		expanded, err := a.expandIssueCommandInput(cmd.Remainder)
+		if err != nil {
+			a.emitInputExpansionError(err)
+			return
+		}
+		a.cmdDiagnose(expanded)
 	case "/fix":
-		a.cmdFix(strings.TrimSpace(strings.TrimPrefix(input, "/fix")))
+		expanded, err := a.expandIssueCommandInput(cmd.Remainder)
+		if err != nil {
+			a.emitInputExpansionError(err)
+			return
+		}
+		a.cmdFix(expanded)
 	case "/bugs":
-		a.cmdBugs(parts[1:])
+		a.cmdBugs(args)
 	case "/__bug_detail":
-		a.cmdBugDetail(parts[1:])
+		a.cmdBugDetail(args)
 	case "/claim":
-		a.cmdClaim(parts[1:])
+		a.cmdClaim(args)
 	case "/close":
-		a.cmdClose(parts[1:])
+		a.cmdClose(args)
 	case "/dock":
 		a.cmdDock()
 	case "/skill":
-		a.cmdSkill(parts[1:])
+		if err := a.handleRawSkillCommand(cmd.Remainder); err != nil {
+			a.emitInputExpansionError(err)
+		}
 	case "/skill-add":
-		a.cmdSkillAddInput(strings.TrimSpace(strings.TrimPrefix(input, "/skill-add")))
+		a.cmdSkillAddInput(cmd.Remainder)
 	case "/skill-update":
 		a.cmdSkillUpdate()
 	case "/help":
 		a.cmdHelp()
 	default:
-		// Check if the command matches a skill name directly (e.g. /pdf → /skill pdf).
-		skillName := strings.TrimPrefix(parts[0], "/")
-		if a.skillLoader != nil {
-			if _, err := a.skillLoader.Load(skillName); err == nil {
-				a.cmdSkill(append([]string{skillName}, parts[1:]...))
-				return
+		if handled, err := a.handleSkillAliasCommand(cmd.Name, cmd.Remainder); handled {
+			if err != nil {
+				a.emitInputExpansionError(err)
 			}
+			return
 		}
 		a.EventCh <- model.Event{
 			Type:    model.AgentReply,
-			Message: fmt.Sprintf("Unknown command: %s. Type /help for available commands.", parts[0]),
+			Message: fmt.Sprintf("Unknown command: %s. Type /help for available commands.", cmd.Name),
+		}
+	}
+}
+
+func (a *Application) handleRawSkillCommand(rawInput string) error {
+	if strings.TrimSpace(rawInput) == "" {
+		a.cmdSkill(nil)
+		return nil
+	}
+
+	skillName, request := splitFirstToken(rawInput)
+	if skillName == "" {
+		a.cmdSkill(nil)
+		return nil
+	}
+
+	if request != "" {
+		expanded, err := a.expandInputText(request)
+		if err != nil {
+			return err
 		}
+		request = expanded
 	}
+
+	a.runSkillCommand(skillName, request)
+	return nil
+}
+
+func (a *Application) handleSkillAliasCommand(commandName, rawRemainder string) (bool, error) {
+	if a.skillLoader == nil {
+		return false, nil
+	}
+
+	skillName := strings.TrimPrefix(strings.TrimSpace(commandName), "/")
+	if skillName == "" {
+		return false, nil
+	}
+	if _, err := a.skillLoader.Load(skillName); err != nil {
+		return false, nil
+	}
+
+	request := strings.TrimSpace(rawRemainder)
+	if request != "" {
+		expanded, err := a.expandInputText(request)
+		if err != nil {
+			return true, err
+		}
+		request = expanded
+	}
+
+	a.runSkillCommand(skillName, request)
+	return true, nil
 }
 
 func (a *Application) cmdModel(args []string) {
@@ -320,6 +386,11 @@ func (a *Application) cmdSkill(args []string) {
 	}
 
 	skillName := args[0]
+	userRequest := strings.TrimSpace(strings.Join(args[1:], " "))
+	a.runSkillCommand(skillName, userRequest)
+}
+
+func (a *Application) runSkillCommand(skillName, userRequest string) {
 	content, err := a.skillLoader.Load(skillName)
 	if err != nil {
 		a.EventCh <- model.Event{
@@ -365,7 +436,6 @@ func (a *Application) cmdSkill(args []string) {
 		Summary:  fmt.Sprintf("loaded skill: %s", skillName),
 	}
 
-	userRequest := strings.TrimSpace(strings.Join(args[1:], " "))
 	if userRequest == "" {
 		userRequest = defaultSkillRequest(skillName)
 	}
@@ -437,6 +507,14 @@ Keybindings:
   /          Start a slash command
   ctrl+c     Cancel/Quit (press twice to exit)
 
+@file Input Expansion:
+  Plain chat and /report, /diagnose, /fix, /skill, /<skill> alias support standalone @relative/path
+  Typing @path in the composer shows file completion candidates before submit
+  Use @@name to keep a literal @name token
+  @path injects a workspace file reference as an absolute path marker; the agent can read it if needed
+  Referenced paths must stay inside the workspace and point to an existing file
+  Invalid @file references fail the whole input
+
 Environment Variables:
   MSCLI_PROVIDER          Provider (openai-completion/openai-responses/anthropic)
   MSCLI_BASE_URL          Base URL