Linux's MAX_ARG_STRLEN caps any single argv element at 128 KB
(32 * PAGE_SIZE). The previous heredoc-in-the-command-string approach
in _write_to_sandbox put the entire tool result inside the 'bash -c'
arg, so any result over ~128 KB raised OSError [Errno 7] 'Argument
list too long' before the heredoc ever ran. The caller logged a
warning, but quiet_mode (CLI default) sets tools.* to ERROR — so the
warning never reached agent.log either, and the agent saw a 1.5 KB
preview tagged 'Full output could not be saved to sandbox'. Hits
delegate_task with 3+ subagent outputs routinely now.
Switch to passing content via env.execute(stdin_data=...). cmd is
now just 'mkdir -p X && cat > Y' (under 1 KB), and the heavyweight
payload travels through stdin where there is no argv-element limit.
E2E reproduced the user's exact 144,778-char delegate_task envelope:
old code OSError'd, new code round-trips cleanly to disk with all
three task summaries intact.
_write_to_sandbox interpolated storage_dir and remote_path directly into
a shell command passed to env.execute(). Paths containing shell
metacharacters (spaces, semicolons, $(), backticks) could trigger
arbitrary command execution inside the sandbox.
Fix: wrap both paths with shlex.quote(). Clean paths (alphanumeric +
slashes/hyphens/dots) are left unmodified by shlex.quote, so existing
behavior is unchanged. Paths with unsafe characters get single-quoted.
Tests added for spaces, $(command) substitution, and semicolon injection.
Add BudgetConfig dataclass to centralize and make overridable the
hardcoded constants (50K per-result, 200K per-turn, 2K preview) that
control when tool outputs get persisted to sandbox. Configurable at
the RL environment level via HermesAgentEnvConfig fields, threaded
through HermesAgentLoop to the storage layer.
Resolution: pinned (read_file=inf) > env config overrides > registry
per-tool > default. CLI override: --env.turn_budget_chars 80000
