Parse and stringify HTTP headers (lowercase, Set-Cookie arrays, round-trip) via @mukundakatta/headers-mcp

Recipe: Parse & Stringify HTTP Headers via @mukundakatta/headers-mcp v0.1.0

Install & run: npm install @mukundakatta/headers-mcp && node node_modules/@mukundakatta/headers-mcp/dist/server.js (stdio)

Tools (2)

Verified Execution Trace (11 calls, 100% success, p50=11ms)

parse({text: "Content-Type: application/json\r\nAuthorization: Bearer tok123\r\nX-Request-ID: abc-def\r\nCache-Control: max-age=3600, must-revalidate"})
  => {"headers":{"content-type":"application/json","authorization":"Bearer tok123","x-request-id":"abc-def","cache-control":"max-age=3600, must-revalidate"}} [148ms]

parse({text: "Set-Cookie: session=abc; Path=/; HttpOnly; Secure\r\nSet-Cookie: lang=en; Path=/; Max-Age=86400"})
  => {"headers":{"set-cookie":["session=abc; Path=/; HttpOnly; Secure","lang=en; Path=/; Max-Age=86400"]}} [32ms]

parse({text: "Accept: text/html, application/xhtml+xml, application/xml;q=0.9, */*;q=0.8\r\nAccept-Language: en-US,en;q=0.5\r\nAccept-Encoding: gzip, deflate, br"})
  => {"headers":{"accept":"text/html, application/xhtml+xml, application/xml;q=0.9, */*;q=0.8","accept-language":"en-US,en;q=0.5","accept-encoding":"gzip, deflate, br"}} [6ms]

parse({text: "X-Forwarded-For: 192.168.1.1, 10.0.0.1, 172.16.0.1\r\nX-Real-IP: 192.168.1.1"})
  => {"headers":{"x-forwarded-for":"192.168.1.1, 10.0.0.1, 172.16.0.1","x-real-ip":"192.168.1.1"}} [8ms]

parse({text: "Content-Disposition: attachment; filename=\"report.pdf\""})
  => {"headers":{"content-disposition":"attachment; filename=\"report.pdf\""}} [14ms]

parse({text: ""})
  => {"headers":{}} [56ms]

stringify({headers: {"Content-Type":"application/json","X-Custom":"hello world","Authorization":"Bearer secret"}})
  => "Content-Type: application/json\r\nX-Custom: hello world\r\nAuthorization: Bearer secret" [11ms]

stringify({headers: {"Cache-Control":"no-cache, no-store","Pragma":"no-cache","Expires":"0"}})
  => "Cache-Control: no-cache, no-store\r\nPragma: no-cache\r\nExpires: 0" [3ms]

parse({text: "Host: example.com\r\nConnection: keep-alive\r\nUser-Agent: pathfinder/1.0"})
  => {"headers":{"host":"example.com","connection":"keep-alive","user-agent":"pathfinder/1.0"}} [9ms]

Key Gotchas

1. Param is `text` NOT `raw` — using raw silently fails with Cannot read properties of undefined.
2. Names always lowercased — Content-Type becomes content-type.
3. `set-cookie` always returns array even with a single value.
4. `stringify` expects a FLAT object — passing {headers: {...}} (the parse output) returns "headers: [object Object]". Extract .headers first.
5. Empty string → `{headers: {}}` — no error on empty input.
6. No header-value parsing — quality values (q=0.9), directives (max-age=3600), and params (filename="...") are kept as raw strings, not decomposed.
7. First call ~148ms (JIT), subsequent calls 3-56ms.