Module login_pty 

Shared pieces for running a provider CLI’s login under a PTY and reading its OAuth URL out of the output: used by the desktop host (agentmux-cef commands/cli_login.rs) and by srv’s auth.* (agentmux-srv server/identity_auth_spawn.rs, identity/auth_patterns.rs). docs/specs/SPEC_PROVIDER_LOGIN_THROUGH_SRV_2026_10_09.md.

Structs

DsrRespondingReader

Wraps the raw PTY reader and transparently answers a cursor-position query (see DSR_CURSOR_POSITION_QUERY) the moment it appears anywhere in the stream — not just at startup, since a TUI could plausibly re-probe after a resize — passing every byte through unchanged to the caller (the query’s own bytes included; they’re harmless noise to the caller’s line-scanning loop, not worth the extra complexity of stripping them from the pass-through).

TerminalLine

A line of terminal output with its escape sequences removed: the visible text, and the target of every OSC-8 hyperlink it carried.

Constants

DSR_CURSOR_POSITION_QUERY

Device Status Report cursor-position query — some CLIs (confirmed: Claude Code, on detecting a real TTY) send this immediately and BLOCK waiting for the terminal to reply with ESC[<row>;<col>R before printing anything else at all. A bare portable_pty handle has no attached terminal emulator to answer this automatically — nothing does, on any platform, without code specifically watching for it — so the child hangs forever and the whole capture loop below times out having seen zero bytes. This is the confirmed root cause of issue #2429 (“no PTY output captured… despite correct binary resolution”): isolated repro (a standalone portable_pty harness spawning the exact same binary/args) showed the child’s first and ONLY output was these 4 bytes, then silence: answering this one query unblocked it immediately, and it printed its OAuth URL within half a second.

DSR_CURSOR_POSITION_REPLY

Synthetic “row 1, col 1” reply. The actual reported position doesn’t matter to these CLIs — confirmed by the repro above — they only need something to answer so their TTY-capability probe stops blocking.

LOGIN_PTY_COLS

Columns for a login PTY. Wide enough that the CLI’s own line-wrapping never wraps the OAuth URL. At 80 cols it did — Claude Code prints “If the browser didn’t open, visit: ” as plain text and hard-wraps it mid-query-string, so only a truncated fragment missing client_id and everything after it was captured (issue #2429). 4096 comfortably covers any realistic query string.

Functions

extract_auth_url

Extract an OAuth URL from a line of CLI output: an https:// URL that looks like an auth URL, from an OSC-8 link target first, else from the visible text.

strip_terminal_codes

Remove terminal escape sequences from line. Two families matter here: