`wrangler-4-111-0-0-b`

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Question

My wrangler config sets legacy_env = true and deploys now fail. What happened, and what should the config look like?

Answer key

A correct answer says: Wrangler no longer supports service environments: the `legacy_env` field and `--legacy-env` flag are gone (the field now raises an error) and every environment deploys as its own Worker named <name>-<environment>.
The stale answer: You can set `legacy_env = false` in wrangler.toml to use service environments, where all environments belong to one Worker.

Answer

Your installed wrangler (4.148.0) no longer accepts the `legacy_env` field. Its config validation now treats any `legacy_env` key as an error, which is why deploys fail (`node_modules/wrangler/wrangler-dist/cli.js:20314`). Service environments have been removed. Each environment now deploys as its own Worker named `<name>-<environment>`, which is what `legacy_env = true` already did, and that was the default. So the fix is to delete the line. Nothing else changes, and your Worker deploys the same way as before.

The config should look like this, with any `env` blocks kept as they are:

```jsonc
{
  "name": "bench-worker",
  "main": "src/index.js",
  "compatibility_date": "2026-10-01"
}
```

The `wrangler.jsonc` in this directory already looks like that and has no `legacy_env`. If deploys still fail, check whether a different config file or an environment-specific one still sets it.

Answering cost $0.16.

Grade

correct

The judge's reason: It says the legacy_env field now errors, service environments are removed, and each environment deploys as its own <name>-<environment> Worker, with no stale claims.

The judge's log

Session log

What the agent wrote, the tools it called, and what they returned, from docs/bench/2026-10-11-done3/runs/B-project-sync/wrangler-4-111-0-0-b.jsonl. Thinking and the session's settings are left out. The raw log

Tool call: Glob
```
{
  "pattern": "wrangler.*"
}
```

Tool output

wrangler.jsonc
node_modules\wrangler\bin\wrangler.js
node_modules\.bin\wrangler.cmd
node_modules\.bin\wrangler.ps1

Tool call: Bash

{
  "command": "cd \"C:/Users/haya0/AppData/Local/Temp/ludion-bench-9geni9/work\" && ls -a && cat package.json 2>/dev/null; ls node_modules/wrangler 2>/dev/null | head",
  "description": "List project files and check wrangler install"
}

Tool output

.
..
.ludion
CLAUDE.md
node_modules
package-lock.json
package.json
src
wrangler.jsonc
{
  "name": "bench-wrangler",
  "private": true,
  "type": "module",
  "scripts": { "dev": "wrangler dev", "deploy": "wrangler deploy" },
  "devDependencies": { "wrangler": "4.148.0" }
}
README.md
bin
config-schema.json
kv-asset-handler.js
package.json
templates
wrangler-dist

Tool call: Bash

{
  "command": "cd \"C:/Users/haya0/AppData/Local/Temp/ludion-bench-9geni9/work\" && cat wrangler.jsonc; grep -o '.\\{300\\}legacy_env.\\{300\\}' node_modules/wrangler/wrangler-dist/cli.js | head -5; grep -n -i legacy_env node_modules/wrangler/config-schema.json | head",
  "description": "Show config and search wrangler source for legacy_env"
}

Tool output

{
  "name": "bench-worker",
  "main": "src/index.js",
  "compatibility_date": "2026-10-01"
}

Tool call: Bash

{
  "command": "cd \"C:/Users/haya0/AppData/Local/Temp/ludion-bench-9geni9/work\" && grep -rl -i \"legacy_env\\|legacyEnv\" node_modules/wrangler/wrangler-dist | head; grep -o -i '.\\{200\\}legacy.env.\\{200\\}' -r node_modules/wrangler/wrangler-dist | head -5",
  "description": "Search wrangler dist for legacy_env references"
}

Tool output

node_modules/wrangler/wrangler-dist/cli.js

Tool call: Bash

{
  "command": "cd \"C:/Users/haya0/AppData/Local/Temp/ludion-bench-9geni9/work\" && grep -n -i -o '.\\{0,250\\}legacy_\\?env.\\{0,250\\}' node_modules/wrangler/wrangler-dist/cli.js | head -8",
  "description": "Show legacy_env context in wrangler cli"
}

Tool output (error)

This Bash command contains multiple operations. The following part requires approval: cd "C:/Users/haya0/AppData/Local/Temp/ludion-bench-9geni9/work" && grep -n -i -o '.\{0,250\}legacy_\?env.\{0,250\}' node_modules/wrangler/wrangler-dist/cli.js

Tool call: Grep

{
  "pattern": ".{0,250}legacy_?env.{0,250}",
  "path": "C:\\Users\\haya0\\AppData\\Local\\Temp\\ludion-bench-9geni9\\work\\node_modules\\wrangler\\wrangler-dist\\cli.js",
  "output_mode": "content",
  "-o": true,
  "-i": true,
  "head_limit": 8
}

Tool output

20314:  if ("legacy_env" in rawConfig) {
20318:					The "legacy_env" field is no longer supported, so please remove it from your configuration file.
20319:					Service environments have been removed, and each environment is now deployed as its own Worker named "<name>-<environment>". This matches the behaviour of "legacy_env = true", which was the default, so removing the field will not change how your Worker is deployed.
20324:    delete rawConfig.legacy_env;
158925:  return typeof error53 === "object" && error53 !== null && "code" in error53 && (error53.code === WORKER_NOT_FOUND_ERR_CODE || error53.code === WORKER_LEGACY_ENVIRONMENT_NOT_FOUND_ERR_CODE);
158927:var WORKER_NOT_FOUND_ERR_CODE, WORKER_LEGACY_ENVIRONMENT_NOT_FOUND_ERR_CODE;
158932:    WORKER_LEGACY_ENVIRONMENT_NOT_FOUND_ERR_CODE = 10090;

Tool call: Read

{
  "file_path": "C:\\Users\\haya0\\AppData\\Local\\Temp\\ludion-bench-9geni9\\work\\node_modules\\wrangler\\wrangler-dist\\cli.js",
  "offset": 20310,
  "limit": 18
}

Tool output

20310	    rawConfig,
20311	    configPath,
20312	    userConfigPath
20313	  );
20314	  if ("legacy_env" in rawConfig) {
20315	    if (!isRedirectedConfig2) {
20316	      diagnostics.errors.push(
20317	        dedent`
20318						The "legacy_env" field is no longer supported, so please remove it from your configuration file.
20319						Service environments have been removed, and each environment is now deployed as its own Worker named "<name>-<environment>". This matches the behaviour of "legacy_env = true", which was the default, so removing the field will not change how your Worker is deployed.
20320						Refer to https://developers.cloudflare.com/workers/wrangler/environments/ for more information.
20321					`
20322	      );
20323	    }
20324	    delete rawConfig.legacy_env;
20325	  }
20326	  validateOptionalProperty(
20327	    diagnostics,

Agent

Your installed wrangler (4.148.0) no longer accepts the `legacy_env` field. Its config validation now treats any `legacy_env` key as an error, which is why deploys fail (`node_modules/wrangler/wrangler-dist/cli.js:20314`). Service environments have been removed. Each environment now deploys as its own Worker named `<name>-<environment>`, which is what `legacy_env = true` already did, and that was the default. So the fix is to delete the line. Nothing else changes, and your Worker deploys the same way as before.

The config should look like this, with any `env` blocks kept as they are:

```jsonc
{
  "name": "bench-worker",
  "main": "src/index.js",
  "compatibility_date": "2026-10-01"
}
```

The `wrangler.jsonc` in this directory already looks like that and has no `legacy_env`. If deploys still fail, check whether a different config file or an environment-specific one still sets it.