Grep

Grep searches the latest indexed snapshots of repositories you can access in Codemod. Use it to find structural code patterns, text matches, or advanced ast-grep rules across your organization or personal Git account. Open Grep at app.codemod.com/grep.

Codemod Grep searches private and organization repositories you have granted Codemod access to. Public structural search across open-source repositories lives at grep.codemod.com.

Prerequisites

Sign in to Codemod.
Connect GitHub or GitLab so repositories appear in your scope.
Index the repositories you want to search. Listing and searching never start indexing automatically.

Repository scope follows the app context: the active organization when one is selected, or your personal Git repositories otherwise.

Search indexed code

Open Grep

Go to Grep in the Codemod app.

Index repositories (first run)

If no repositories are searchable yet, select the repositories to index and start indexing. Wait until they show as searchable before you run a query.When some repositories are already searchable, use Add repositories to index more without leaving the search studio.

Choose a mode and write a query

Pick Pattern, Regex, or YAML, then enter the query. Optionally narrow by language, repository, and path filter.

Review matches

Results group by repository and file, with snippets, exact line ranges, and links back to GitHub or GitLab. Use pagination to load more files when the result set continues.

Query modes

Mode	Use when	Example
Pattern	You want structural matches with ast-grep pattern syntax and metavariables	`console.log($$$ARGS)`
Regex	You want text, names, or messages (PostgreSQL regular expressions)	`class\s+StandardScaler`
YAML	You need a full ast-grep rule with `language` and `rule` (optional `constraints` / `utils`)	A single YAML document containing `language` and `rule`

Prefer Pattern for source-code searches and YAML for multi-condition or constrained ast-grep rules. Use Regex when the target is genuinely textual, the language parser is unsupported, or a precise ast-grep query cannot be formed.

Pattern and YAML run through Codemod’s indexed ast-grep engine. Regex runs as a PostgreSQL regular expression against decrypted snapshot content inside the database. Interactive Grep does not execute user-authored JavaScript.

Filters

Language: search all indexed languages in scope, or limit to one or more parsers.
Repositories: omit the filter to search every searchable repository in the current scope, or select a subset.
Path: optional glob, contains, prefix, or basename filter to limit which files are considered.

YAML mode uses the language declared in the YAML document. That top-level language is authoritative for the rule.

Results

Successful searches return:

Match counts and truncated state when limits apply
File-grouped snippets with exact ranges (not full source files)
Provider links to the indexed commit on GitHub or GitLab
Partial failures for repositories that are not indexed, lack the selected language, or fail during execution

Check coverage before concluding that code is absent

Returned snippets remain useful even when some repositories fail. A zero-match page does not prove that code is absent when coverage is incomplete. If your search reports repository failures, inspect those failures and narrow the language, path, or expression within the scope you intended to search. Avoid repeatedly submitting the same failing query. When more pages are available, continue the same search. Changing the query, mode, repositories, language, or path starts a new search; do not reuse a continuation cursor from the old search. Reuse snippets and focused source ranges for files you already found.

Grep MCP

MCP clients can search the same repository scope through Codemod MCP:

https://app.codemod.com/api/v1/mcp

Authenticate with a Codemod API key that has Use Grep enabled, or with OAuth for the full tool set:

{
  "mcpServers": {
    "codemod-grep": {
      "type": "http",
      "url": "https://app.codemod.com/api/v1/mcp",
      "headers": {
        "Authorization": "Bearer ${CODEMOD_API_KEY}"
      }
    }
  }
}

API keys expose Grep read tools only (grep_list_repositories, grep_search, grep_read_ranges, and related Grep reads). OAuth can also index and create Insights dashboards when scopes allow. Index repositories in the Grep UI (or with grep_index_* under OAuth) before searching from an MCP client. Store the key in a secret or environment variable. Do not commit it into MCP configuration files.

Agent workflow

Narrow path, language, and repositories when you can.
Call grep_search — MCP returns a small text page (~12 KiB) with a coverage header such as [matches 1–N of ≥M in F files], numbered snippets, and per-file readHints for follow-up reads.
Share the leading Grep <absolute URL> short link unchanged so a person can open the same search.
Pull more source with grep_read_ranges using those readHints (or known ranges). Do not paste large dumps into chat.
Continue with one cursor and identical inputs when the page says more: — either the search cursor or an outputCursor for buffered text. Cursors expire after about 30 minutes.
For naming variants (snake / Pascal / camel), prefer grep_multi_search with labelled queries instead of many separate searches.

Default MCP fileLimit is 20 matching files per page (max 1,000). Optional definitionsOnly with mode=regex prefers declaration-like matches on page 1.

Select supported languages

For grep_search, use the scalar "all" or a non-empty array of parser names advertised in the tool’s input schema, such as ["go", "typescript"]. ["all"] is not a valid selection. Neither markdown nor makefile is a supported parser value. If a language selection is rejected, choose supported parsers that match your intended scope. Use "all" only when you intend to search all indexed languages; unsupported selections are not silently broadened.

Interpret search results

MCP search and range tools return text only (no structuredContent on those calls). Trust the coverage header and more: footer in the text. Before claiming absence or exhaustive coverage:

Partial repository failures do not mark the tool result as a hard error when matching files are still present — keep usable evidence and inspect failures separately.
Incomplete coverage (countComplete: false or a continuation footer) is not proof of absence, even with zero matches on the page.
Continue with identical inputs when a cursor is present. Changing query, mode, repositories, language, or path starts a new search; do not reuse an old cursor.

Create Insights dashboards from Grep

Use Grep for exploratory searches, then promote a useful query into a persistent Insights dashboard. The dashboard keeps the query and repository scope as editable configuration so you can track the same pattern over time—with Insights features such as timeseries trends, table breakdowns, and group-by dimensions like repository or codeowner (team ownership). Grep finds the matches. Insights turns that search into ongoing visibility.

Run a Grep search

Complete a Pattern, Regex, or YAML search against the repositories you care about. Refine language and path filters until the results look right.

Create an Insights dashboard

After results load, choose Create Insights dashboard. Name the dashboard, confirm which repositories to include (up to 10), and select the languages to track.

Review and extend in Insights

Open the new dashboard to see the generated match-total and repository-breakdown widgets. From there, add timeseries charts, ownership breakdowns, formulas, or additional queries using the normal Insights editor.

What Grep hands off:

The exact query, mode, optional path filter, and selected repositories
Count-oriented widgets for total matches and per-repository breakdown
Languages you chose at creation time (fewer languages usually compute faster)

What it does not copy into Insights:

Match snippets, file paths, or individual result rows from the Grep UI

After creation, the dashboard is a normal Insights dashboard: you can edit widgets, change repositories, and use template variables under the usual Insights permissions.

Prefer a focused language selection when creating the dashboard. Searching with language all in Grep is fine for discovery; for tracking, choose only the languages you need so Insights stays faster.

Regex dashboards use Insights/JSSG regex semantics, which can differ slightly from interactive Grep’s PostgreSQL regex results.

Troubleshooting

Symptom	What to try
No repositories appear	Connect GitHub or GitLab, confirm app install permissions, and switch to the correct organization if you work in one.
Search returns not indexed	Index the repository from Grep, wait until it is searchable, then retry.
Invalid MCP language selection	Use scalar `"all"`, not `["all"]`, or a non-empty array of supported parser names from the input schema. Do not mix unsupported parser names into the array.
Unsupported language failures	Narrow the language filter to supported languages present in the indexed snapshot. Select `all` only if you intend to broaden the search.
Partial failures or incomplete counts	Keep usable snippets, inspect the failures, and narrow the search. Do not treat zero results or a null cursor as proof of absence.
Pattern finds nothing that Regex finds	Confirm the Pattern query is complete, valid syntax for the language, and not a bare text fragment.
MCP searches fail with auth errors	Use an API key with Use Grep enabled, or OAuth with `grep:read`. Organization keys require the creator to still be a member. Endpoint is `/api/v1/mcp` (not a Grep-only path).
MCP page looks truncated	Expected — pages are ~12 KiB. Use `readHints` with `grep_read_ranges`, or continue with the same cursor and identical inputs.
Cursor rejected after a pause	Cursors expire after about 30 minutes. Re-run the search with identical inputs.

Insights

Track pattern adoption and migration progress with dashboards.

ast-grep YAML queries

Reuse ast-grep rules in Insights widgets.

Investigation

Turn Grep searches into a source-backed answer about code behavior.

Codemod MCP

Connect assistants to Grep, Insights, and other Codemod tools.

GitHub integration

Grant repository access so Grep can index and search your code.

First steps

Community

Enterprise

Other Resources

Prerequisites

Search indexed code

Query modes

Filters

Results

Check coverage before concluding that code is absent

Grep MCP

Agent workflow

Select supported languages

Interpret search results

Create Insights dashboards from Grep

Troubleshooting

Insights

ast-grep YAML queries

Investigation

Codemod MCP

GitHub integration

​Prerequisites

​Search indexed code

​Query modes

​Filters

​Results

​Check coverage before concluding that code is absent

​Grep MCP

​Agent workflow

​Select supported languages

​Interpret search results

​Create Insights dashboards from Grep

​Troubleshooting

​Related docs

Insights

ast-grep YAML queries

Investigation

Codemod MCP

GitHub integration

Prerequisites

Search indexed code

Query modes

Filters

Results

Check coverage before concluding that code is absent

Grep MCP

Agent workflow

Select supported languages

Interpret search results

Create Insights dashboards from Grep

Troubleshooting

Related docs