Grep passes an empty file type to ripgrep

[ivkhokhlov]

What version of Kimi Code is running?

0.38.0

Which open platform/subscription were you using?

OpenAI-compatible provider

Which model were you using?

gpt-5.6-sol

What platform is your computer?

Linux 7.0.0-30-generic x86_64 x86_64

What issue are you seeing?

When the model invokes the built-in Grep tool with an empty optional file type, Kimi Code forwards the empty string to ripgrep:

Grep input: { "pattern": "example", "type": "" }

Failed to grep: rg: unrecognized file type:

This can repeat within a session as the agent retries the same tool call. It creates avoidable tool failures and consumes context even though no file-type filter was requested.

The current schemas accept any string, including an empty one:

• packages/agent-core/src/tools/builtin/file/grep.ts
• packages/agent-core-v2/src/agent/tools/os/grep/grep.ts

Both implementations then check only whether the value is undefined:

if (args.glob !== undefined) cmd.push('--glob', args.glob);
if (args.type !== undefined) cmd.push('--type', args.type);

Consequently, type: "" becomes rg --type ''. Running that command directly reproduces the same error with ripgrep exit code 2:

$ rg --type '' anything .
rg: unrecognized file type:
$ echo $?
2

The same boundary issue applies to an empty glob, although ripgrep does not necessarily report it in the same way.

What steps can reproduce the bug?

1. Run Kimi Code 0.38.0 in a workspace where rg is available.

2. Have the model call the built-in Grep tool with input equivalent to:

   {
     "pattern": "example",
     "type": ""
   }

3. Observe that Kimi Code executes ripgrep with --type followed by an empty argument.

4. Observe rg: unrecognized file type: and a failed Grep tool result.

The implementation-level reproduction is deterministic because the argument builder appends --type whenever args.type !== undefined.

What is the expected behavior?

Optional string filters containing only whitespace should be treated as omitted after trimming. Kimi Code should not pass an empty --type or --glob value to ripgrep.

A focused fix could normalize the optional arguments at the tool boundary, for example:

const glob = args.glob?.trim();
const type = args.type?.trim();
if (glob) cmd.push('--glob', glob);
if (type) cmd.push('--type', type);

Regression tests should cover empty and whitespace-only values in both agent-core implementations, while preserving valid trimmed values.

Additional information

Confirmed against current main at commit e6a302b310a78fb0c09ea20169c52541980a9a87:

• v1 schema:

  kimi-code/packages/agent-core/src/tools/builtin/file/grep.ts

  Lines 55 to 67 in e6a302b

  	glob: z
  	.string()
  	.optional()
  	.describe(
  	"Optional glob filter for which files to search, e.g. `*.ts`. Matched against each file's full absolute path, so a path-anchored pattern like `src/**/*.ts` silently matches nothing — use a basename pattern (`*.ts`), or anchor with `**/` (`**/src/**/*.ts`). To scope the search to a directory, use `path` instead.",
  	),
  	type: z
  	.string()
  	.optional()
  	.describe(
  	'Optional ripgrep file type filter, such as ts or py. Prefer this over `glob` when filtering by language or file kind: it is more efficient and less error-prone than an equivalent glob pattern.',
  	),
  	output_mode: z

• v1 argument builder:

  kimi-code/packages/agent-core/src/tools/builtin/file/grep.ts

  Lines 486 to 487 in e6a302b

  	if (args.glob !== undefined) cmd.push('--glob', args.glob);
  	if (args.type !== undefined) cmd.push('--type', args.type);

• v2 schema:

  kimi-code/packages/agent-core-v2/src/agent/tools/os/grep/grep.ts

  Lines 14 to 26 in e6a302b

  	glob: z
  	.string()
  	.optional()
  	.describe(
  	"Optional glob filter for which files to search, e.g. `*.ts`. Matched against each file's full absolute path, so a path-anchored pattern like `src/**/*.ts` silently matches nothing — use a basename pattern (`*.ts`), or anchor with `**/` (`**/src/**/*.ts`). To scope the search to a directory, use `path` instead.",
  	),
  	type: z
  	.string()
  	.optional()
  	.describe(
  	'Optional ripgrep file type filter, such as ts or py. Prefer this over `glob` when filtering by language or file kind: it is more efficient and less error-prone than an equivalent glob pattern.',
  	),
  	output_mode: z

• v2 argument builder:

  kimi-code/packages/agent-core-v2/src/agent/tools/os/grep/grepTool.ts

  Lines 457 to 458 in e6a302b

  	if (args.glob !== undefined) cmd.push('--glob', args.glob);
  	if (args.type !== undefined) cmd.push('--type', args.type);

I searched existing open issues for the exact ripgrep error and did not find a matching report.

I am willing to submit a focused PR with regression tests after a maintainer approves this bug with /approve, as required by CONTRIBUTING.md.