feat: default to pretty output, add --json and --jq flags

[Ramon Nogueira (ramon-langchain)]

Summary

• Change default output format from json to pretty (human-readable tables/trees)
• Add --json flag as shorthand for --format json
• Add --jq EXPR flag to apply jq expressions to JSON output (powered by gojq, implies --json)

Example usage:

langsmith project list                          # pretty table (new default)
langsmith project list --json                   # JSON output
langsmith project list --jq '.[].name'          # extract names via jq
langsmith project list --jq '[.[] | select(.run_count > 100)]'

Release Note

Default output is now human-readable; use --json or --jq for machine-readable output.

Test Plan

• All existing tests pass with updated default expectations
• New unit tests for applyJQ covering field access, array indexing, select, pipes, keys, length, nested access, invalid expressions, and nil input
• Integration tests for OutputJSON with and without JQExpr
• Flag wiring tests: --jq implies JSON format, --json flag, flag defaults

[devin-ai-integration]

Devin Review found 1 potential issue.

🐛 1 issue in files not directly in the diff

🐛 --json and --jq flags silently ignored by api ls and api info commands (internal/cmdutil/resolve.go:45-51)

The api ls and api info subcommands resolve their output format via cmdutil.ResolveFormat(cmd) (internal/cmdutil/resolve.go:45-51), which only reads the --format flag. The new --json and --jq persistent flags added to the root command are accepted by cobra (they're inherited persistent flags) but have no effect on these commands. For example, langsmith api ls --json will still render a pretty table because cmdutil.ResolveFormat returns "pretty" (the new default) without checking the --json or --jq flags. Meanwhile, all other subcommands use cmd.GetFormat() (internal/cmd/root.go:107-111) which correctly checks both flagJSON and flagJQ. This creates an inconsistency where --json works everywhere except the api subcommands.

View 4 additional findings in Devin Review.