fix(ai-chat): clearer tool-call validation error for dropped pageId in parallel batches (#190)

In-app AI-chat tools used bare zod schemas, so when the model dropped a
required arg (typically pageId) in a parallel/batch tool call, the AI SDK
forwarded zod's raw "expected string, received undefined" text to the model
— not actionable. Add a centralized modelFriendlyInput(shape) wrapper that
keeps the exact JSON Schema contract (required/description/constraints via
z.toJSONSchema draft-7) but replaces the raw zod text with a message naming
each missing/invalid parameter and reminding the model not to drop ids like
pageId in parallel batches. No value is guessed/backfilled (cf. #159).

Applied to every in-app tool: the sharedTool() builder and all inline
inputSchema in ai-chat-tools.service.ts, plus public-share-chat-tools.service.ts.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/server/src/core/ai-chat/tools/ai-chat-tools.service.spec.ts

@@ -120,18 +120,25 @@ describe('AiChatToolsService deletePage guardrail (H4)', () => {
     const tools = await buildTools();
     const deletePage = tools.deletePage;
 
-    // The Zod input schema only allows `pageId`; parsing strips/ignores extra
+    // The wrapped input schema (modelFriendlyInput) only allows `pageId`;
-    // keys, so a permanent/force flag is never part of the validated input.
+    // validation strips/ignores extra keys, so a permanent/force flag is never
+    // part of the validated input handed to execute.
     const schema = (deletePage as unknown as { inputSchema: unknown })
       .inputSchema as {
-      parse: (v: unknown) => Record<string, unknown>;
+      validate: (
+        v: unknown,
+      ) =>
+        | { success: boolean; value?: Record<string, unknown> }
+        | Promise<{ success: boolean; value?: Record<string, unknown> }>;
     };
-    const parsed = schema.parse({
+    const result = await schema.validate({
       pageId: 'page-789',
       permanentlyDelete: true,
       forceDelete: true,
     });
 
+    expect(result.success).toBe(true);
+    const parsed = result.value as Record<string, unknown>;
     expect(parsed).toHaveProperty('pageId', 'page-789');
     expect(parsed).not.toHaveProperty('permanentlyDelete');
     expect(parsed).not.toHaveProperty('forceDelete');
@@ -207,19 +214,26 @@ describe('AiChatToolsService expanded toolset guardrails', () => {
     const tools = await buildTools();
     const transformPage = tools.transformPage;
 
-    // The Zod input schema only allows pageId/transformJs/dryRun; parsing
+    // The wrapped input schema only allows pageId/transformJs/dryRun;
-    // strips unknown keys, so deleteComments can never reach the client.
+    // validation strips unknown keys, so deleteComments can never reach the
+    // client.
     const schema = (transformPage as unknown as { inputSchema: unknown })
       .inputSchema as {
-      parse: (v: unknown) => Record<string, unknown>;
+      validate: (
+        v: unknown,
+      ) =>
+        | { success: boolean; value?: Record<string, unknown> }
+        | Promise<{ success: boolean; value?: Record<string, unknown> }>;
     };
-    const parsed = schema.parse({
+    const result = await schema.validate({
       pageId: 'p',
       transformJs: '(d)=>d',
       dryRun: true,
       deleteComments: true,
     });
 
+    expect(result.success).toBe(true);
+    const parsed = result.value as Record<string, unknown>;
     expect(parsed).toHaveProperty('pageId', 'p');
     expect(parsed).not.toHaveProperty('deleteComments');
   });
@@ -395,3 +409,95 @@ describe('AiChatToolsService node-arg JSON-string coercion', () => {
     expect(updatePageJsonCalls).toHaveLength(0);
   });
 });
+
+/**
+ * Model-friendly tool-call validation (#190): when the model drops a required
+ * `pageId` in a parallel/batch tool call, the built-in input schema must return
+ * a CLEAR, actionable message (naming the parameter, reminding it not to drop
+ * ids in batches) instead of zod's raw "expected string, received undefined" —
+ * while a valid call still validates. This is wired centrally via
+ * modelFriendlyInput, so it applies to every in-app tool; createComment (the
+ * tool from the bug report) and a sharedTool-built tool (getPage's sibling
+ * getOutline) are exercised here end-to-end through forUser().
+ */
+describe('AiChatToolsService model-friendly input validation (#190)', () => {
+  const fakeClient: Partial<DocmostClientLike> = {};
+  const tokenServiceStub = {
+    generateAccessToken: jest.fn().mockResolvedValue('access-token'),
+    generateCollabToken: jest.fn().mockResolvedValue('collab-token'),
+  };
+  let service: AiChatToolsService;
+
+  beforeEach(() => {
+    jest.spyOn(loader, 'loadDocmostMcp').mockResolvedValue(
+      mockLoaded(function () {
+        return fakeClient as DocmostClientLike;
+      } as unknown as loader.DocmostClientCtor),
+    );
+    service = new AiChatToolsService(
+      tokenServiceStub as never,
+      {} as never,
+      {} as never,
+      {} as never,
+      {} as never,
+    );
+  });
+
+  afterEach(() => jest.restoreAllMocks());
+
+  function buildTools() {
+    return service.forUser(
+      { id: 'user-1', email: 'u@example.com', workspaceId: 'ws-1' } as never,
+      'session-1',
+      'ws-1',
+      'chat-1',
+    );
+  }
+
+  // The AI SDK Schema produced by modelFriendlyInput exposes `validate`.
+  type ValidatableSchema = {
+    validate: (
+      v: unknown,
+    ) =>
+      | { success: boolean; value?: unknown; error?: Error }
+      | Promise<{ success: boolean; value?: unknown; error?: Error }>;
+  };
+  const inputSchemaOf = (t: unknown) =>
+    (t as { inputSchema: unknown }).inputSchema as ValidatableSchema;
+
+  it('createComment: a dropped pageId yields a clear, model-actionable message', async () => {
+    const tools = await buildTools();
+    // The exact failing shape from the bug report's second parallel batch:
+    // content + selection, but pageId silently dropped.
+    const result = await inputSchemaOf(tools.createComment).validate({
+      content: 'A remark',
+      selection: 'титановый проводник',
+    });
+    expect(result.success).toBe(false);
+    expect(result.error?.message).toContain('parameter "pageId": missing (required)');
+    expect(result.error?.message).toContain('parallel/batch tool calls');
+    // Not the raw zod text the model previously received.
+    expect(result.error?.message).not.toContain('received undefined');
+  });
+
+  it('createComment: a valid call with pageId validates successfully', async () => {
+    const tools = await buildTools();
+    const result = await inputSchemaOf(tools.createComment).validate({
+      pageId: '019efe44-0000-0000-0000-000000000000',
+      content: 'A remark',
+      selection: 'титановый проводник',
+    });
+    expect(result.success).toBe(true);
+    expect(result.value).toMatchObject({
+      pageId: '019efe44-0000-0000-0000-000000000000',
+      content: 'A remark',
+    });
+  });
+
+  it('sharedTool-built tools (getOutline) also get the friendly message on a dropped pageId', async () => {
+    const tools = await buildTools();
+    const result = await inputSchemaOf(tools.getOutline).validate({});
+    expect(result.success).toBe(false);
+    expect(result.error?.message).toContain('parameter "pageId": missing (required)');
+  });
+});

apps/server/src/core/ai-chat/tools/ai-chat-tools.service.ts

@@ -15,6 +15,7 @@ import {
 } from './docmost-client.loader';
 import { resolveCurrentPageResult } from './current-page.util';
 import { parseNodeArg } from './parse-node-arg';
+import { modelFriendlyInput } from './model-friendly-input';
 
 /**
  * Per-user, per-request adapter that exposes Docmost READ operations to the
@@ -102,9 +103,13 @@ export class AiChatToolsService {
     ): Tool =>
       tool({
         description: spec.description,
-        inputSchema: spec.buildShape
+        // Wrap via modelFriendlyInput so a dropped/invalid parameter (e.g. a
-          ? z.object(spec.buildShape(z) as z.ZodRawShape)
+        // pageId omitted in a parallel batch, #190) yields a clear, actionable
-          : z.object({}),
+        // tool error instead of zod's raw text. No-arg specs still get an empty
+        // object schema.
+        inputSchema: modelFriendlyInput(
+          spec.buildShape ? (spec.buildShape(z) as z.ZodRawShape) : {},
+        ),
         execute,
       });
 
@@ -118,7 +123,7 @@ export class AiChatToolsService {
           'and entities), not a full sentence. If the first results look weak ' +
           'or incomplete, search again with different wording or synonyms ' +
           'before answering.',
-        inputSchema: z.object({
+        inputSchema: modelFriendlyInput({
           query: z.string().describe('The search query.'),
           limit: z
             .number()
@@ -227,7 +232,7 @@ export class AiChatToolsService {
           '"the current page", or "here" refers to. Returns the page id and title, ' +
           'or null if the user is not currently on a page. Call this first whenever ' +
           'the user refers to the current page without giving an explicit id.',
-        inputSchema: z.object({}),
+        inputSchema: modelFriendlyInput({}),
         execute: async () => resolveCurrentPageResult(openedPage),
       }),
 
@@ -235,7 +240,7 @@ export class AiChatToolsService {
         description:
           'Fetch a single page as Markdown by its page id. Returns the page ' +
           'title and its Markdown content.',
-        inputSchema: z.object({
+        inputSchema: modelFriendlyInput({
           pageId: z.string().describe('The id (or slugId) of the page.'),
         }),
         execute: async ({ pageId }) => {
@@ -259,7 +264,7 @@ export class AiChatToolsService {
           'Create a new page with a Markdown body in a space, optionally under ' +
           'a parent page. Returns the new page id and title. Reversible: a page ' +
           'can be moved to trash later.',
-        inputSchema: z.object({
+        inputSchema: modelFriendlyInput({
           title: z.string().describe('The title of the new page.'),
           content: z
             .string()
@@ -294,7 +299,7 @@ export class AiChatToolsService {
         description:
           "Replace a page's body with new Markdown content (and optionally its " +
           'title). Reversible: the previous version is kept in page history.',
-        inputSchema: z.object({
+        inputSchema: modelFriendlyInput({
           pageId: z.string().describe('The id of the page to update.'),
           content: z.string().describe('The new page body as Markdown.'),
           title: z
@@ -316,7 +321,7 @@ export class AiChatToolsService {
         description:
           "Rename a page (change its title only; the body is untouched). " +
           'Reversible: rename back at any time.',
-        inputSchema: z.object({
+        inputSchema: modelFriendlyInput({
           pageId: z.string().describe('The id of the page to rename.'),
           title: z.string().describe('The new title.'),
         }),
@@ -331,7 +336,7 @@ export class AiChatToolsService {
         description:
           'Move a page under a new parent page, or to the space root when no ' +
           'parent is given. Reversible: move it back at any time.',
-        inputSchema: z.object({
+        inputSchema: modelFriendlyInput({
           pageId: z.string().describe('The id of the page to move.'),
           parentPageId: z
             .string()
@@ -353,7 +358,7 @@ export class AiChatToolsService {
         description:
           'Move a page to the trash (SOFT delete only — fully reversible; the ' +
           'page can be restored from trash). This NEVER permanently deletes.',
-        inputSchema: z.object({
+        inputSchema: modelFriendlyInput({
           pageId: z.string().describe('The id of the page to move to trash.'),
         }),
         // GUARDRAIL (§14 H4): the only field ever passed to the client is
@@ -379,7 +384,7 @@ export class AiChatToolsService {
           '"selection not found" error, retry with a corrected EXACT selection ' +
           'copied verbatim from a single paragraph/block. Reversible via the ' +
           'comment UI.',
-        inputSchema: z.object({
+        inputSchema: modelFriendlyInput({
           pageId: z.string().describe('The id of the page to comment on.'),
           content: z.string().describe('The comment body as Markdown.'),
           selection: z
@@ -428,7 +433,7 @@ export class AiChatToolsService {
         description:
           'Resolve or reopen a top-level comment thread (reversible — toggle ' +
           'the resolved flag). Only top-level comments can be resolved.',
-        inputSchema: z.object({
+        inputSchema: modelFriendlyInput({
           commentId: z
             .string()
             .describe('The id of the top-level comment to resolve/reopen.'),
@@ -460,7 +465,7 @@ export class AiChatToolsService {
           'List the most recent pages, optionally scoped to a single space. ' +
           'Returns a bounded list (default 50, max 100). Pass tree:true (with ' +
           "spaceId) to instead get the space's full page hierarchy as a nested tree.",
-        inputSchema: z.object({
+        inputSchema: modelFriendlyInput({
           spaceId: z
             .string()
             .optional()
@@ -488,7 +493,7 @@ export class AiChatToolsService {
           'List sidebar pages for a space. With no pageId, returns the ' +
           "space's ROOT pages; with a pageId, returns that page's direct " +
           'CHILDREN.',
-        inputSchema: z.object({
+        inputSchema: modelFriendlyInput({
           spaceId: z.string().describe('The id of the space.'),
           pageId: z
             .string()
@@ -520,7 +525,7 @@ export class AiChatToolsService {
         description:
           'Read a table as a matrix of cell texts (plus a parallel cellIds ' +
           'matrix so cells can be addressed for rich edits).',
-        inputSchema: z.object({
+        inputSchema: modelFriendlyInput({
           pageId: z.string().describe('The id of the page.'),
           tableRef: z
             .string()
@@ -536,7 +541,7 @@ export class AiChatToolsService {
       listComments: tool({
         description:
           'List all comments on a page (content as Markdown).',
-        inputSchema: z.object({
+        inputSchema: modelFriendlyInput({
           pageId: z.string().describe('The id of the page.'),
         }),
         execute: async ({ pageId }) => await client.listComments(pageId),
@@ -544,7 +549,7 @@ export class AiChatToolsService {
 
       getComment: tool({
         description: 'Fetch a single comment by id (content as Markdown).',
-        inputSchema: z.object({
+        inputSchema: modelFriendlyInput({
           commentId: z.string().describe('The id of the comment.'),
         }),
         execute: async ({ commentId }) => await client.getComment(commentId),
@@ -554,7 +559,7 @@ export class AiChatToolsService {
         description:
           'Find new comments across a space (optionally scoped to a subtree) ' +
           'created after a given timestamp.',
-        inputSchema: z.object({
+        inputSchema: modelFriendlyInput({
           spaceId: z.string().describe('The id of the space to scan.'),
           since: z
             .string()
@@ -586,7 +591,7 @@ export class AiChatToolsService {
         description:
           'Fetch a single page-history version including its lossless ' +
           'ProseMirror content.',
-        inputSchema: z.object({
+        inputSchema: modelFriendlyInput({
           historyId: z.string().describe('The id of the history version.'),
         }),
         execute: async ({ historyId }) =>
@@ -604,7 +609,7 @@ export class AiChatToolsService {
           'Export a page to a single self-contained Docmost-flavoured ' +
           'Markdown file (meta + body + comment threads). Lossless round-trip ' +
           'with importPageMarkdown.',
-        inputSchema: z.object({
+        inputSchema: modelFriendlyInput({
           pageId: z.string().describe('The id of the page to export.'),
         }),
         execute: async ({ pageId }) => {
@@ -630,7 +635,7 @@ export class AiChatToolsService {
           '{"type":"text","text":"x","marks":[{"type":"bold"}]}. The node arg ' +
           'may be a JSON object or a JSON string (both accepted). Reversible: ' +
           'the previous version is kept in page history.',
-        inputSchema: z.object({
+        inputSchema: modelFriendlyInput({
           pageId: z.string().describe('The id of the page.'),
           nodeId: z
             .string()
@@ -663,7 +668,7 @@ export class AiChatToolsService {
           '{"type":"text","text":"x","marks":[{"type":"bold"}]}. The node arg ' +
           'may be a JSON object or a JSON string (both accepted). Reversible ' +
           'via page history.',
-        inputSchema: z.object({
+        inputSchema: modelFriendlyInput({
           pageId: z.string().describe('The id of the page.'),
           node: z
             .any()
@@ -722,7 +727,7 @@ export class AiChatToolsService {
           'object or a JSON string (both accepted). Omit content for a ' +
           'title-only update. Reversible: the previous version is kept in page ' +
           'history.',
-        inputSchema: z.object({
+        inputSchema: modelFriendlyInput({
           pageId: z.string().describe('The id of the page to update.'),
           content: z
             .any()
@@ -753,7 +758,7 @@ export class AiChatToolsService {
         description:
           'Insert a row of plain-text cells into a table. Reversible via ' +
           'page history.',
-        inputSchema: z.object({
+        inputSchema: modelFriendlyInput({
           pageId: z.string().describe('The id of the page.'),
           tableRef: z
             .string()
@@ -772,7 +777,7 @@ export class AiChatToolsService {
       tableDeleteRow: tool({
         description:
           'Delete a table row at a 0-based index. Reversible via page history.',
-        inputSchema: z.object({
+        inputSchema: modelFriendlyInput({
           pageId: z.string().describe('The id of the page.'),
           tableRef: z
             .string()
@@ -787,7 +792,7 @@ export class AiChatToolsService {
         description:
           'Set the plain-text content of a table cell at [row, col] (0-based). ' +
           'Reversible via page history.',
-        inputSchema: z.object({
+        inputSchema: modelFriendlyInput({
           pageId: z.string().describe('The id of the page.'),
           tableRef: z
             .string()
@@ -817,7 +822,7 @@ export class AiChatToolsService {
           'Make a page PUBLICLY accessible and return its public URL. ' +
           'Reversible via unsharePage. Only share when the user explicitly ' +
           'asked, since this exposes the page to anyone with the link.',
-        inputSchema: z.object({
+        inputSchema: modelFriendlyInput({
           pageId: z.string().describe('The id of the page to share.'),
           searchIndexing: z
             .boolean()
@@ -844,7 +849,7 @@ export class AiChatToolsService {
           "page's ProseMirror document for complex/scripted rewrites. dryRun " +
           '(default true) previews a diff WITHOUT writing; set dryRun:false to ' +
           'apply. Reversible: applying creates a new page-history snapshot.',
-        inputSchema: z.object({
+        inputSchema: modelFriendlyInput({
           pageId: z.string().describe('The id of the page to transform.'),
           transformJs: z
             .string()

apps/server/src/core/ai-chat/tools/model-friendly-input.spec.ts

@@ -0,0 +1,101 @@
+import { z } from 'zod';
+import {
+  modelFriendlyInput,
+  buildModelFriendlyMessage,
+} from './model-friendly-input';
+
+/**
+ * Unit tests for the centralized in-app tool input wrapper (#190). A dropped or
+ * invalid parameter must surface a clear, model-actionable message (naming the
+ * parameter and reminding the model not to drop ids in parallel batches), while
+ * a valid call validates cleanly and strips unknown keys — and the advertised
+ * JSON Schema keeps the unchanged required/description contract.
+ */
+describe('modelFriendlyInput', () => {
+  // Mirrors createComment's shape: pageId is the required id the model drops in
+  // parallel batches; selection is optional with a min length.
+  const shape = {
+    pageId: z.string().describe('The id of the page to comment on.'),
+    content: z.string().describe('The comment body as Markdown.'),
+    selection: z.string().min(1).max(250).optional(),
+  };
+
+  // Loose return type: the AI SDK ValidationResult is a discriminated union, but
+  // these tests assert on both branches, so a flat optional shape is simpler.
+  async function validate(
+    value: unknown,
+  ): Promise<{ success: boolean; value?: unknown; error?: Error }> {
+    const schema = modelFriendlyInput(shape);
+    return await schema.validate!(value);
+  }
+
+  it('rejects a dropped required pageId with a clear, actionable message', async () => {
+    const result = await validate({
+      content: 'Looks off here',
+      selection: 'титановый проводник',
+    });
+    expect(result.success).toBe(false);
+    const msg = result.error?.message ?? '';
+    // Names the dropped parameter...
+    expect(msg).toContain('parameter "pageId": missing (required)');
+    // ...and gives an explicit, non-raw instruction (not zod's raw text).
+    expect(msg).toContain('parallel/batch tool calls');
+    expect(msg).not.toContain('expected string, received undefined');
+  });
+
+  it('distinguishes a present-but-invalid parameter from a missing one', async () => {
+    // selection is present but too short (invalid), pageId is missing.
+    const result = await validate({ content: 'x', selection: '' });
+    expect(result.success).toBe(false);
+    const msg = result.error?.message ?? '';
+    expect(msg).toContain('parameter "pageId": missing (required)');
+    expect(msg).toContain('parameter "selection": invalid');
+  });
+
+  it('accepts a valid call and strips unknown keys from the validated value', async () => {
+    const result = await validate({
+      pageId: 'page-1',
+      content: 'A comment',
+      selection: 'anchor text',
+      bogus: true,
+    });
+    expect(result.success).toBe(true);
+    if (!result.success) throw new Error('expected success');
+    expect(result.value).toEqual({
+      pageId: 'page-1',
+      content: 'A comment',
+      selection: 'anchor text',
+    });
+    expect(result.value).not.toHaveProperty('bogus');
+  });
+
+  it('preserves the required/description contract in the advertised JSON Schema', async () => {
+    const schema = modelFriendlyInput(shape);
+    const json = (await schema.jsonSchema) as {
+      required?: string[];
+      properties?: Record<string, { description?: string }>;
+    };
+    // pageId + content stay required; selection stays optional.
+    expect(json.required).toEqual(expect.arrayContaining(['pageId', 'content']));
+    expect(json.required).not.toContain('selection');
+    expect(json.properties?.pageId.description).toBe(
+      'The id of the page to comment on.',
+    );
+  });
+
+  it('handles a no-arg tool (empty shape) without error', async () => {
+    const schema = modelFriendlyInput({});
+    const result = await schema.validate!({});
+    expect(result.success).toBe(true);
+  });
+});
+
+describe('buildModelFriendlyMessage', () => {
+  it('falls back to a generic message when issues carry an empty path', () => {
+    // safeParse on a non-object yields a root-level issue (empty path).
+    const error = z.object({ a: z.string() }).safeParse('not-an-object');
+    if (error.success) throw new Error('expected failure');
+    const msg = buildModelFriendlyMessage(error.error, 'not-an-object');
+    expect(msg).toContain('parameter "input"');
+  });
+});

apps/server/src/core/ai-chat/tools/model-friendly-input.ts

@@ -0,0 +1,93 @@
+import { jsonSchema, type Schema } from 'ai';
+import type { JSONSchema7 } from '@ai-sdk/provider';
+import { z } from 'zod';
+
+/**
+ * Centralized input-schema wrapper for every in-app AI-chat tool.
+ *
+ * THE PROBLEM (#190): when the model issues PARALLEL / batch tool calls it
+ * sometimes drops an "obvious" repeated required argument (typically `pageId`)
+ * from some of the calls. zod v4 correctly rejects the missing value, but the
+ * AI SDK forwards zod's RAW message ("Invalid input: expected string, received
+ * undefined") straight back to the model, which is not actionable — the model
+ * cannot tell WHICH parameter it dropped or that it must re-send it.
+ *
+ * THE FIX: keep the exact same validation, but replace the raw zod text with a
+ * model-friendly message that names every problematic parameter and tells the
+ * model to re-issue the call with all required parameters present. We do NOT
+ * guess/backfill the value (a silently-assumed "current page" could comment on
+ * the wrong page — cf. #159); the model is simply told to retry correctly.
+ *
+ * HOW IT WORKS: we build the tool's JSON Schema from the zod shape via
+ * `z.toJSONSchema(..., { target: 'draft-7' })` (so the advertised contract —
+ * `required` / `description` / field constraints — is unchanged) and hand the
+ * AI SDK a custom `validate` that runs `z.object(shape).safeParse(value)`. On
+ * failure the AI SDK wraps our returned `Error` in `InvalidToolInputError`, so
+ * our clear text is what reaches the model as the tool error.
+ */
+export function modelFriendlyInput<T extends z.ZodRawShape>(
+  shape: T,
+): Schema<z.output<z.ZodObject<T>>> {
+  const objectSchema = z.object(shape);
+  // draft-07 keeps required/description/constraints intact, matching what the
+  // model already saw — the tool contract does not change.
+  const json = z.toJSONSchema(objectSchema, {
+    target: 'draft-7',
+  }) as JSONSchema7;
+
+  return jsonSchema<z.output<z.ZodObject<T>>>(json, {
+    validate: (value) => {
+      const result = objectSchema.safeParse(value);
+      if (result.success) {
+        return { success: true, value: result.data };
+      }
+      return {
+        success: false,
+        error: new Error(buildModelFriendlyMessage(result.error, value)),
+      };
+    },
+  });
+}
+
+/**
+ * Turn a zod validation failure into a clear, model-actionable message naming
+ * each problematic parameter (and whether it is missing vs. invalid), plus an
+ * explicit reminder not to drop required ids in parallel/batch tool calls.
+ */
+export function buildModelFriendlyMessage(
+  error: z.ZodError,
+  value: unknown,
+): string {
+  const seen = new Set<string>();
+  const parts: string[] = [];
+  for (const issue of error.issues) {
+    const name = issue.path.length ? issue.path.map(String).join('.') : 'input';
+    // A parameter the model omitted entirely reads as `undefined` at its path;
+    // anything else is present-but-invalid (wrong type, too short, etc.).
+    const missing = valueAtPath(value, issue.path) === undefined;
+    const part = `parameter "${name}": ${missing ? 'missing (required)' : 'invalid'}`;
+    if (seen.has(part)) continue;
+    seen.add(part);
+    parts.push(part);
+  }
+  if (parts.length === 0) {
+    // Defensive: a ZodError always has issues, but never emit an empty list.
+    parts.push('input: invalid');
+  }
+  return (
+    `Invalid input for this tool — ${parts.join('; ')}. ` +
+    'Re-issue the call with EVERY required parameter present and valid. ' +
+    "Do not drop ids like pageId, even when making parallel/batch tool calls — " +
+    'each tool call must carry its own pageId.'
+  );
+}
+
+/** Read the value at a zod issue path; returns undefined if any hop is absent. */
+function valueAtPath(value: unknown, path: ReadonlyArray<PropertyKey>): unknown {
+  let current: unknown = value;
+  for (const key of path) {
+    if (current === null || typeof current !== 'object') return undefined;
+    current = (current as Record<PropertyKey, unknown>)[key];
+  }
+  return current;
+}

apps/server/src/core/ai-chat/tools/public-share-chat-tools.service.ts

@@ -5,6 +5,7 @@ import { ShareService } from '../../share/share.service';
 import { SearchService } from '../../search/search.service';
 import { PageRepo } from '@docmost/db/repos/page/page.repo';
 import { jsonToMarkdown } from '../../../collaboration/collaboration.util';
+import { modelFriendlyInput } from './model-friendly-input';
 
 /**
  * Isolated, READ-ONLY toolset for the ANONYMOUS public-share assistant.
@@ -52,7 +53,7 @@ export class PublicShareChatToolsService {
           '(key terms and entities), not a full sentence. If the first ' +
           'results look weak, search again with different wording before ' +
           'answering. Only pages inside this share are ever returned.',
-        inputSchema: z.object({
+        inputSchema: modelFriendlyInput({
           query: z.string().describe('The search query.'),
           limit: z
             .number()
@@ -87,7 +88,7 @@ export class PublicShareChatToolsService {
           'Markdown, by its page id. Returns the page title and its Markdown ' +
           'content. Only pages inside this share can be read; reading any ' +
           'other page fails.',
-        inputSchema: z.object({
+        inputSchema: modelFriendlyInput({
           pageId: z
             .string()
             .describe('The id (or slugId) of a page within this share.'),
@@ -142,7 +143,7 @@ export class PublicShareChatToolsService {
           'List the pages (titles + ids) that make up THIS published ' +
           'documentation share, so you can orient yourself before reading or ' +
           'searching. Only pages inside this share are listed.',
-        inputSchema: z.object({}),
+        inputSchema: modelFriendlyInput({}),
         execute: async () => {
           // Reuse the same share-tree logic the public /shares/tree route uses:
           // it validates the share + workspace, excludes restricted subtrees,