tools: two-tier discovery (surface listing + on-demand prompt)

BuildRuntime now appends a compact surface listing (name + one-liner)
to the preamble instead of full tool prompts. Full prompts are
available on-demand via ToolPrompt(name) for the /net/dns pattern.

- DiscoverTools: extracts short description from first content line
- BuildRuntime: appends "# Available Tools" with name + description
- ToolPrompt(name): returns full ollie:prompt for a specific tool

pkg/agent/core.go

@@ -163,16 +163,17 @@ func BuildRuntime(cfg *config.Config, d tools.Dispatcher, cwd string, env []stri
 		}
 	}
 
-	// Append tool prompts discovered from script headers.
-	var toolPrompts strings.Builder
+	// Append compact tool surface listing (name + description).
+	// Full prompts are available on-demand via /tools write (net/dns pattern).
+	var toolListing strings.Builder
 	for _, ti := range allToolInfos {
-		if ti.Prompt != "" {
-			toolPrompts.WriteString(ti.Prompt)
-			toolPrompts.WriteByte('\n')
+		if ti.Description != "" && ti.Server == "" {
+			// Only named tool scripts (Server==""), not built-in executors
+			fmt.Fprintf(&toolListing, "- **%s** — %s\n", ti.Name, ti.Description)
 		}
 	}
-	if toolPrompts.Len() > 0 {
-		preamble += "\n" + toolPrompts.String()
+	if toolListing.Len() > 0 {
+		preamble += "\n# Available Tools\n\n" + toolListing.String()
 	}
 
 	return &Runtime{

pkg/tools/execute/tool.go

@@ -210,8 +210,7 @@ func ExtractPrompt(script string) string {
 }
 
 // DiscoverTools scans the tools directory and returns metadata for all scripts,
-// including their ollie:prompt blocks. Used to populate the /tools file and
-// inject tool prompts into the system prompt.
+// including their ollie:prompt blocks and short descriptions.
 func DiscoverTools() []tools.ToolInfo {
 	dir := ToolsPath()
 	entries, err := os.ReadDir(dir)
@@ -227,15 +226,44 @@ func DiscoverTools() []tools.ToolInfo {
 		if err != nil {
 			continue
 		}
-		prompt := ExtractPrompt(string(data))
+		script := string(data)
+		prompt := ExtractPrompt(script)
+		desc := extractShortDescription(prompt)
 		infos = append(infos, tools.ToolInfo{
-			Name:   e.Name(),
-			Prompt: prompt,
+			Name:        e.Name(),
+			Description: desc,
+			Prompt:      prompt,
 		})
 	}
 	return infos
 }
 
+// extractShortDescription gets the first non-heading, non-empty line from a prompt.
+func extractShortDescription(prompt string) string {
+	for _, line := range strings.Split(prompt, "\n") {
+		line = strings.TrimSpace(line)
+		if line == "" || strings.HasPrefix(line, "#") {
+			continue
+		}
+		return line
+	}
+	return ""
+}
+
+// ToolPrompt returns the full ollie:prompt content for a named tool.
+// Returns "" if the tool has no prompt or doesn't exist.
+func ToolPrompt(name string) string {
+	if strings.Contains(name, "/") || strings.Contains(name, "..") {
+		return ""
+	}
+	path := filepath.Join(ToolsPath(), name)
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return ""
+	}
+	return ExtractPrompt(string(data))
+}
+
 // ReadTool reads a named tool script from the tools directory.
 func ReadTool(name string) (string, error) {
 	if strings.Contains(name, "/") || strings.Contains(name, "..") {