`rtk curl` breaks downstream parsers by returning compressed schema instead of raw payload when stdout is piped

Summary

rtk curl always returns a token-compressed, schema-like representation of the response body, regardless of whether stdout is a TTY or a pipe. This silently breaks any command that pipes rtk curl into a parser expecting the raw payload (python -c "json.load(sys.stdin)", jq, node -e, awk, sed, etc.).

Because the Claude Code hook (rtk-rewrite.sh) auto-rewrites curl → rtk curl, this affects every such pipeline the LLM constructs — even though the LLM never sees the rtk-compressed output, only the downstream parser error.

Reproduction

# Expected: prints "Hello World"
curl -s "https://api.mymemory.translated.net/get?q=Bonjour%20monde&langpair=fr%7Cen" \
  | python3 -c "import json,sys; d=json.load(sys.stdin); print(d['responseData']['translatedText'])"

Under the Claude Code hook (or when the user explicitly writes rtk curl), this pipeline fails:

json.decoder.JSONDecodeError: Expecting property name enclosed in double quotes: line 2 column 3 (char 4)

Because rtk curl returns:

{
  exception_code: null,
  matches:
  [{
      create-date: string,
      created-by: string,
      ...

instead of the raw JSON body that json.load expects.

Impact

Any LLM-generated pipeline using curl | <parser> breaks silently.
Root cause is opaque to the LLM: the tool sees a JSONDecodeError and blames its own parsing code, not rtk.
The Claude Code hook compounds the issue: users running curl ... | jq from the assistant never typed rtk, yet get hit by it.
Other rtk subcommands that transform output (rtk aws, rtk psql, rtk json, rtk cat) likely have the same class of bug.

Root cause

rtk curl is not a passthrough — it post-processes the response body for LLM consumption. This is correct behavior when an LLM is the consumer. It is incorrect when a parser is the consumer.

The tool currently has no way to distinguish those two cases.

Suggested fix

Detect isatty(stdout) at startup. If stdout is not a TTY (i.e., it is piped, redirected to a file, or captured), skip the compression layer and passthrough the raw response bytes from the underlying curl.

This matches the long-standing Unix convention followed by ls, grep, diff, etc., which disable colors and column formatting when piped.

// pseudo-code inside rtk curl
if !io::stdout().is_terminal() {
    return run_native_curl_passthrough(args);
}
// else: existing compression path

The same fix should apply to every rtk subcommand that transforms output (cat, read, json, aws, psql, git, gh, etc.).

Alternative / workaround

Users can prefix with rtk proxy <cmd> to bypass rewriting. But the Claude Code hook rewrites curl unconditionally, so the LLM has to remember to write rtk proxy curl every time it pipes, which does not scale.
Users can set [hooks] exclude_commands = ["curl"] in ~/.config/rtk/config.toml, but this disables all rtk curl savings globally, even when the LLM IS the consumer.

Neither replaces a proper TTY-aware passthrough inside rtk itself.

Environment

rtk: 0.34.3
OS: Linux 6.17
Shell: bash
Claude Code hook: hooks/rtk-rewrite.sh (rtk-hook-version: 3)

Checklist

rtk curl passes through raw bytes when stdout is not a TTY
Same behavior for rtk cat, rtk read, rtk json, rtk aws, rtk psql, rtk git, rtk gh
Add a test matrix: piped to jq, python -c "json.load", file redirect, /dev/null
Document the TTY-aware behavior in the README

rtk-upstream-issue.md 3.6 KB Geçmiş Ham

rtk curl breaks downstream parsers by returning compressed schema instead of raw payload when stdout is piped