Logs

Every line a service prints is assembled, classified once, kept in a bounded in-memory buffer, written to disk and streamed to whoever is watching: the TUI, Atlas Desktop and MCP clients.

From pipe to line#

• Real lines are assembled from the raw pipe. A partial line (a prompt such as Password: ) shows after 150 ms of silence; \r\n is one line break; a lone \r keeps only the last state of a progress bar; invalid UTF-8 is replaced with �; a line over 16 KiB is cut and ends with … [truncated].
• Level (error, warn, info, debug), timestamp and a sequence number are computed once, when the line arrives.
• When a service starts again after printing output, a dim ──── HH:MM:SS restarted ──── rule separates the runs. It is never searched or counted as output.

Levels are inferred from the text: error, err , fatal, panic or red ANSI are error; warn or yellow are warn; debug, trace or gray are debug; the rest are info.

Buffers#

Each service keeps its own ring in memory: the last 50,000 lines and at most 8 MiB, whichever comes first. A chatty service cannot push out another service’s history. All merges the rings in arrival order. The full history is on disk.

On disk#

<project>/.logs/<service>.log holds HH:MM:SS [stdout|stderr] text with ANSI stripped. The previous run is rotated to <service>.prev.log when a service is spawned again, and a log that grows past 50 MB rotates the same way. Output of actions is written to .logs/action-<slug>.log. The complete file list is in Runtime › Files in .logs/.

Viewing logs#

Where	How
TUI	/ find, Tab find/filter, Ctrl+R regex, v level, V time range, ]e / ]w error and warning jumps, } / { and o for links. See TUI › Log viewer
Desktop	The Logs tab: ⌘F find with regex and case toggles, service chips with error counts, level filter, time range, e / w jumps, ⌘-click on URLs and path:line. See Desktop › Logs
MCP	atlas_logs (tail, level, since_minutes) and atlas_logs_search (substring or /regex/). See MCP
Shell	tail -f .logs/api.log, or atlas dev --headless to stream all services to stdout

Searching#

Find and filter share one matcher: a lowercase query is case-insensitive, an uppercase letter makes it case-sensitive (smartcase), and regex uses the Rust regex syntax. MCP search is always case-insensitive and treats a query wrapped in slashes (/ECONNREFUSED|timeout/) as a regex.

JSON logs#

In the TUI, J turns on JSON compaction: a line that is exactly one JSON object renders as LEVEL message key=value …, colored by level. Pino and bunyan numeric levels (30, 40, 50) and string levels are understood. The raw line is untouched on disk.

Bursts#

The runner never disconnects a slow client. A client that falls behind skips lines and sees an N lines skipped marker; the complete output is still in .logs/. The desktop app receives output in about 16 ms batches. Rendering cost depends on the visible rows, not on the buffer size.

Hiding quiet services#

hide_logs: true on a service removes its tab and keeps its lines out of All. The file in .logs/ is still written. Use it for databases and other chatty infrastructure.