tweak: tool outputs to be more llm friendly (#13269)

packages/opencode/src/tool/edit.ts

@@ -38,7 +38,7 @@ export const EditTool = Tool.define("edit", {
     }
 
     if (params.oldString === params.newString) {
-      throw new Error("oldString and newString must be different")
+      throw new Error("No changes to apply: oldString and newString are identical.")
     }
 
     const filePath = path.isAbsolute(params.filePath) ? params.filePath : path.join(Instance.directory, params.filePath)
@@ -617,7 +617,7 @@ export function trimDiff(diff: string): string {
 
 export function replace(content: string, oldString: string, newString: string, replaceAll = false): string {
   if (oldString === newString) {
-    throw new Error("oldString and newString must be different")
+    throw new Error("No changes to apply: oldString and newString are identical.")
   }
 
   let notFound = true
@@ -647,9 +647,9 @@ export function replace(content: string, oldString: string, newString: string, r
   }
 
   if (notFound) {
-    throw new Error("oldString not found in content")
+    throw new Error(
+      "Could not find oldString in the file. It must match exactly, including whitespace, indentation, and line endings.",
+    )
   }
-  throw new Error(
+  throw new Error("Found multiple matches for oldString. Provide more surrounding context to make the match unique.")
-    "Found multiple matches for oldString. Provide more surrounding lines in oldString to identify the correct match.",
-  )
 }

packages/opencode/src/tool/glob.ts

@@ -62,7 +62,9 @@ export const GlobTool = Tool.define("glob", {
       output.push(...files.map((f) => f.path))
       if (truncated) {
         output.push("")
-        output.push("(Results are truncated. Consider using a more specific path or pattern.)")
+        output.push(
+          `(Results are truncated: showing first ${limit} results. Consider using a more specific path or pattern.)`,
+        )
       }
     }
 

packages/opencode/src/tool/grep.ts

@@ -109,7 +109,8 @@ export const GrepTool = Tool.define("grep", {
       }
     }
 
-    const outputLines = [`Found ${finalMatches.length} matches`]
+    const totalMatches = matches.length
+    const outputLines = [`Found ${totalMatches} matches${truncated ? ` (showing first ${limit})` : ""}`]
 
     let currentFile = ""
     for (const match of finalMatches) {
@@ -127,7 +128,9 @@ export const GrepTool = Tool.define("grep", {
 
     if (truncated) {
       outputLines.push("")
-      outputLines.push("(Results are truncated. Consider using a more specific path or pattern.)")
+      outputLines.push(
+        `(Results truncated: showing ${limit} of ${totalMatches} matches (${totalMatches - limit} hidden). Consider using a more specific path or pattern.)`,
+      )
     }
 
     if (hasErrors) {
@@ -138,7 +141,7 @@ export const GrepTool = Tool.define("grep", {
     return {
       title: params.pattern,
       metadata: {
-        matches: finalMatches.length,
+        matches: totalMatches,
         truncated,
       },
       output: outputLines.join("\n"),