Fix hashline-edit deduplication and validation

- Canonicalize anchors in dedupe keys to handle whitespace variants
- Make lines field required in edit operations
- Only allow unanchored append/prepend to create missing files
- Reorder delete/rename validation to prevent edge cases
- Add allow_non_gpt_model and max_prompt_tokens to config schema
  ```

src/tools/hashline-edit/edit-deduplication.ts

@@ -1,18 +1,24 @@
 import type { HashlineEdit } from "./types"
 import { toNewLines } from "./edit-text-normalization"
+import { normalizeLineRef } from "./validation"
 
 function normalizeEditPayload(payload: string | string[]): string {
   return toNewLines(payload).join("\n")
 }
 
+function canonicalAnchor(anchor: string | undefined): string {
+  if (!anchor) return ""
+  return normalizeLineRef(anchor)
+}
+
 function buildDedupeKey(edit: HashlineEdit): string {
   switch (edit.op) {
     case "replace":
-      return `replace|${edit.pos}|${edit.end ?? ""}|${normalizeEditPayload(edit.lines)}`
+      return `replace|${canonicalAnchor(edit.pos)}|${edit.end ? canonicalAnchor(edit.end) : ""}|${normalizeEditPayload(edit.lines)}`
     case "append":
-      return `append|${edit.pos ?? ""}|${normalizeEditPayload(edit.lines)}`
+      return `append|${canonicalAnchor(edit.pos)}|${normalizeEditPayload(edit.lines)}`
     case "prepend":
-      return `prepend|${edit.pos ?? ""}|${normalizeEditPayload(edit.lines)}`
+      return `prepend|${canonicalAnchor(edit.pos)}|${normalizeEditPayload(edit.lines)}`
     default:
       return JSON.stringify(edit)
   }

src/tools/hashline-edit/edit-operations.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it } from "bun:test"
-import { applyHashlineEdits } from "./edit-operations"
+import { applyHashlineEdits, applyHashlineEditsWithReport } from "./edit-operations"
 import { applyAppend, applyInsertAfter, applyPrepend, applyReplaceLines, applySetLine } from "./edit-operation-primitives"
 import { computeLineHash } from "./hash-computation"
 import type { HashlineEdit } from "./types"
@@ -389,3 +389,23 @@ describe("hashline edit operations", () => {
     expect(result).toEqual("replaced A\nline 3\nreplaced B")
   })
 })
+
+describe("dedupe anchor canonicalization", () => {
+  it("deduplicates edits with whitespace-variant anchors", () => {
+    //#given
+    const content = "line 1\nline 2"
+    const lines = content.split("\n")
+    const canonical = `1#${computeLineHash(1, lines[0])}`
+    const spaced = ` 1 # ${computeLineHash(1, lines[0])} `
+
+    //#when
+    const report = applyHashlineEditsWithReport(content, [
+      { op: "append", pos: canonical, lines: ["inserted"] },
+      { op: "append", pos: spaced, lines: ["inserted"] },
+    ])
+
+    //#then
+    expect(report.deduplicatedEdits).toBe(1)
+    expect(report.content).toBe("line 1\ninserted\nline 2")
+  })
+})

src/tools/hashline-edit/hashline-edit-executor.ts

@@ -33,7 +33,7 @@ function resolveToolCallID(ctx: ToolContextWithCallID): string | undefined {
 
 function canCreateFromMissingFile(edits: HashlineEdit[]): boolean {
   if (edits.length === 0) return false
-  return edits.every((edit) => edit.op === "append" || edit.op === "prepend")
+  return edits.every((edit) => (edit.op === "append" || edit.op === "prepend") && !edit.pos)
 }
 
 function buildSuccessMeta(
@@ -86,19 +86,19 @@ export async function executeHashlineEditTool(args: HashlineEditArgs, context: T
     const filePath = args.filePath
     const { delete: deleteMode, rename } = args
 
+    if (deleteMode && rename) {
+      return "Error: delete and rename cannot be used together"
+    }
+    if (deleteMode && args.edits.length > 0) {
+      return "Error: delete mode requires edits to be an empty array"
+    }
+
     if (!deleteMode && (!args.edits || !Array.isArray(args.edits) || args.edits.length === 0)) {
       return "Error: edits parameter must be a non-empty array"
     }
 
     const edits = deleteMode ? [] : normalizeHashlineEdits(args.edits)
 
-    if (deleteMode && rename) {
-      return "Error: delete and rename cannot be used together"
-    }
-    if (deleteMode && edits.length > 0) {
-      return "Error: delete mode requires edits to be an empty array"
-    }
-
     const file = Bun.file(filePath)
     const exists = await file.exists()
     if (!exists && !deleteMode && !canCreateFromMissingFile(edits)) {

src/tools/hashline-edit/tool-description.ts

@@ -10,7 +10,7 @@ WORKFLOW:
 VALIDATION:
   Payload shape: { "filePath": string, "edits": [...], "delete"?: boolean, "rename"?: string }
   Each edit must be one of: replace, append, prepend
-  Edit shape: { "op": "replace"|"append"|"prepend", "pos"?: "LINE#ID", "end"?: "LINE#ID", "lines"?: string|string[]|null }
+  Edit shape: { "op": "replace"|"append"|"prepend", "pos"?: "LINE#ID", "end"?: "LINE#ID", "lines": string|string[]|null }
   lines must contain plain replacement text only (no LINE#ID prefixes, no diff + markers)
   CRITICAL: all operations validate against the same pre-edit file snapshot and apply bottom-up. Refs/tags are interpreted against the last-read version of the file.
 

src/tools/hashline-edit/tools.test.ts

@@ -341,4 +341,81 @@ describe("createHashlineEditTool", () => {
     //#then
     expect(envelope.lineEnding).toBe("\r\n")
   })
+
+  it("rejects delete=true with non-empty edits before normalization", async () => {
+    //#given
+    const filePath = path.join(tempDir, "delete-reject.txt")
+    fs.writeFileSync(filePath, "line1")
+
+    //#when
+    const result = await tool.execute(
+      {
+        filePath,
+        delete: true,
+        edits: [{ op: "replace", pos: "1#ZZ", lines: "bad" }],
+      },
+      createMockContext(),
+    )
+
+    //#then
+    expect(result).toContain("delete mode requires edits to be an empty array")
+    expect(fs.existsSync(filePath)).toBe(true)
+  })
+
+  it("rejects delete=true combined with rename", async () => {
+    //#given
+    const filePath = path.join(tempDir, "delete-rename.txt")
+    fs.writeFileSync(filePath, "line1")
+
+    //#when
+    const result = await tool.execute(
+      {
+        filePath,
+        delete: true,
+        rename: path.join(tempDir, "new-name.txt"),
+        edits: [],
+      },
+      createMockContext(),
+    )
+
+    //#then
+    expect(result).toContain("delete and rename cannot be used together")
+    expect(fs.existsSync(filePath)).toBe(true)
+  })
+
+  it("rejects missing file creation with anchored append", async () => {
+    //#given
+    const filePath = path.join(tempDir, "nonexistent.txt")
+
+    //#when
+    const result = await tool.execute(
+      {
+        filePath,
+        edits: [{ op: "append", pos: "1#ZZ", lines: ["bad"] }],
+      },
+      createMockContext(),
+    )
+
+    //#then
+    expect(result).toContain("File not found")
+  })
+
+  it("allows missing file creation with unanchored append", async () => {
+    //#given
+    const filePath = path.join(tempDir, "newfile.txt")
+
+    //#when
+    const result = await tool.execute(
+      {
+        filePath,
+        edits: [{ op: "append", lines: ["created"] }],
+      },
+      createMockContext(),
+    )
+
+    //#then
+    expect(fs.existsSync(filePath)).toBe(true)
+    expect(fs.readFileSync(filePath, "utf-8")).toBe("created")
+    expect(result).toBe(`Updated ${filePath}`)
+  })
 })

src/tools/hashline-edit/tools.ts

@@ -31,7 +31,6 @@ export function createHashlineEditTool(): ToolDefinition {
             end: tool.schema.string().optional().describe("Range end anchor in LINE#ID format"),
             lines: tool.schema
               .union([tool.schema.string(), tool.schema.array(tool.schema.string()), tool.schema.null()])
-              .optional()
               .describe("Replacement or inserted lines. null/[] deletes with replace"),
           })
         )

src/tools/hashline-edit/validation.ts

@@ -15,7 +15,7 @@ const MISMATCH_CONTEXT = 2
 
 const LINE_REF_EXTRACT_PATTERN = /([0-9]+#[ZPMQVRWSNKTXJBYH]{2})/
 
-function normalizeLineRef(ref: string): string {
+export function normalizeLineRef(ref: string): string {
   const originalTrimmed = ref.trim()
   let trimmed = originalTrimmed
   trimmed = trimmed.replace(/^(?:>>>|[+-])\s*/, "")