August: Codex hardens, SDKs consolidate security, GPT-5.5 lands

The flagship capability story of the month was the arrival of gpt-5.5 across both major SDKs. openai-node v7.3.0 and v7.4.0 (plus openai-python v2.52.0) added the model and tool metadata fields [1][2][3][4] as part of a coordinated release, and openai-python v2.53.0 capped the month [5]. For teams building on OpenAI, the model name is now first-class in the SDKs, not just a string to pass through.

Both SDKs also invested heavily in security hardening. openai-node shipped several fixes across the month, including a prototype pollution patch, credential leak protections, streaming safety fixes, and X.509 transport examples [6][7]. The X.509 workload identity support landed in openai-node , and openai-python shipped a similar security blitz, plus a credential injection fix and Bedrock Runtime support [8][9]. The pattern is clear: the SDKs are treating transport and credential handling as security boundaries, not just plumbing.

Codex's most notable architectural work was the rollout of a portable agent plugin system and a migration framework for rollout updates. It consolidated MCP config editing into codex-core, moved Cursor-managed skills into Codex, and stopped publishing legacy Linux bundle archives [10][11][12]. The result: Codex's installation story is now more uniform, and its configuration surface is pulled into one place. [9] adds plugin portability across install paths, which matters for teams that ship Codex configurations to multiple environments.

Security and resilience work in Codex was broad but targeted. It hardened the login flow with onboarding hints, preserved SQLite thread metadata during goal mutations, added an MCP conformance regression gate, and fixed an image transparency and path resolution vulnerability [13][14][15]. The MCP conformance gate is a meaningful addition because it converts a previously manual compliance check into an automated one. On the performance side, the TUI stopped querying terminal size on every redraw, and it now supports two-stroke key chords [16][7].

Two policy changes are worth flagging for teams that run Codex. The 'Plan' nudge is gone, and update_plan is now opt-in, not default . Plan-related behavior used to be pushed on users; it is now a choice. That is a breaking change for automated workflows that relied on the default, though it simplifies the tool's interactions for most users. The security posture overall shifted toward "fail closed": several fixes addressed credential leaks and streaming exposures in the SDKs, and the SDKs also completed the Jest to Vitest migration for handwritten Node tests [17][18].