Release notes for Claude Code v2.1.302 (2026-10-16), a hardening release that fixes unbounded memory use in the Read tool, a config-write race, permission-mode and subagent defaults under -p, MCP tool discovery for servers negotiating protocol 2026-07-28, and unbounded hook concurrency. The source pairs it with yoagent 0.25.8 (2026-10-19), whose changes cover the same read-safety theme plus a new set of priced model presets with real context windows.
Key Points
Read tool image handling: images (and pipes/devices named like images) are no longer loaded fully into memory at any size; image sources over 128 MB are refused.
Config write race: subcommands that exited before a queued config write completed could lose the change — now fixed.
-p permission mode: with no permission mode specified on third-party providers, claude -p now starts in default mode.
Fork subagents are on by default in -p.
MCP compatibility: servers negotiating protocol 2026-07-28 while omitting resultType / ttlMs / cacheScope previously exposed no tools; that is fixed.
Hook concurrency: prompt and agent hooks are capped at 12 concurrent per event.
yoagent 0.25.8 adds priced model presets, counts Gemini/Vertex thinking tokens as output, refuses FIFOs/devices in ReadFileTool, and flags promotional pricing that can double the cost read.
Concepts
Read tool / ReadFileTool — the file-and-image ingestion path shared by these agent tools.
Non-regular file — FIFOs and devices that must be rejected before any read or base64 encoding.
Queued config write — asynchronous persistence that can be lost if the process exits early.
— subagent mode enabled by default in non-interactive () runs.
Fork subagents
-p
MCP protocol 2026-07-28 — negotiation version adding resultType, ttlMs, cacheScope; older servers may omit them.
Priced preset — a named model configuration carrying real context windows and rate information.
Promotional rate — a temporary discount that makes the recorded cost read up to 2× off.
Details
Claude Code v2.1.302 (2026-10-16)
1. Bounded image reads. The Read tool previously read an image of any size — or a pipe/device whose name looked like an image — fully into memory. It now refuses image sources over 128 MB. The source compares the guard levels in sibling tooling, which differ in kind and in limit:
So rejecting non-regular files and capping size are two independent defenses; yoyo currently has the first but not the second.
2. Config write durability. A subcommand could exit before a queued configuration write finished, silently dropping the change. The exit path now waits for/completes the write.
3. Non-interactive permission default.claude -p invoked without a permission mode against third-party providers now starts in default mode, removing an ambiguous/implicit state.
4. Subagent default. Fork subagents are enabled by default for -p runs.
5. MCP tool visibility. Servers that negotiated protocol 2026-07-28 but omitted the newer resultType, ttlMs, and cacheScope fields caused zero tools to be registered; the client now tolerates the omission.
6. Hook concurrency cap. Prompt and agent hooks are limited to 12 concurrent executions per event, bounding fan-out on busy events.
yoagent 0.25.8 (2026-10-19)
Priced presets with real windows — named configurations that carry actual context windows and rates rather than generic constructors:
claude_sonnet_5_5, claude_haiku_5_5, gpt_6_1_sol, gemini_4_argon (gemini-4-argon), gemini_3_8_flash, grok_4_7, mistral_large_4, glm_5_3, glm_5_3_flash, qwen_3_8_max, qwen_3_8_flash.
Thinking tokens as output. Gemini/Vertex thinking tokens now count toward output accounting.
Read safety.ReadFileTool gains require_regular_file, refusing FIFOs and devices — the regular-file half of the guard Claude Code and yoyo implement.
Promotional-rate caveat.gemini_4_argon, gemini_3_8_flash, and mistral_large_4 carry the regular rate in their preset; while a promotion is active, the computed cost read can be up to 2× the true charge.
Known gap. As of Day 232, yoyo's google, xai, mistral, and zai arms in create_model_config still use generic constructors and do not pick up these presets.
Guarded read path
Rendering diagram…
Caps vary by tool: 128 MB (Claude Code images), 20 MB (yoagent images), unbounded in yoyo /add.