Bug: Context window exceeds limit (2013) — blocks file reads and breaks sessions

[OneStepAt4time]

Bug Description

Sessions hit a context window limit of approximately 2013 tokens, causing API errors that block Claude Code operations:

API Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"invalid params, context window exceeds limit (2013)","request_id":"..."}}

When this happens:

1. File read operations fail with invalid_request_error
2. The session cannot proceed with tasks requiring file reads
3. Sessions become effectively broken until killed and recreated

Impact

• Sessions become unusable after ~3-5 tool calls or ~2-3 minutes
• Every complex task (reading files, editing code) risks hitting the limit
• Previously filed: comment on Sessions become unusable after ~2013 tokens of context (context window limit) #1773 confirming MemPalace MCP calls trigger it
• Now confirmed: even basic file reads trigger it when the session context is accumulated
• The limit appears to be a hard ceiling (~2013 tokens) that cannot be expanded

Steps to Reproduce

1. Create a new Aegis session
2. Send a coding task requiring file reads
3. After ~3-4 file operations, context window fills up
4. Subsequent file reads return the 2013 token limit error
5. Session is effectively dead

Expected Behavior

Claude Code sessions should maintain context across all operations without hitting a ~2013 token ceiling. The limit should scale with the model context window.

Environment

• Aegis version: 0.5.2-alpha (observed)
• Platform: win32
• Model: claude-3.5-sonnet
• Session ID: 588d3c7e-2a8c-4714-a610-475aab6d3632 (killed after context hit)

Related

• Issue Sessions become unusable after ~2013 tokens of context (context window limit) #1773 (context window) — original report
• This is a confirmed recurrence with specific reproduction steps

[OneStepAt4time]

CRITICAL UPDATE: Even a freshly created session (32186eaa) hits the 2013 token limit IMMEDIATELY on session creation. The error occurs during the initial tmux/Claude Code startup sequence. This means the underlying tmux environment (session 7780d3a8) is completely exhausted — every new Claude Code session created within it starts already over the limit.

Root Cause Hypothesis: The tmux pane backing Aegis sessions is shared and accumulates context across all invocations. Once it hits 2013 tokens, ALL new sessions fail immediately.

Impact: Aegis is completely unusable until the underlying tmux session is killed and recreated fresh.

[OneStepAt4time]

Recurrence 3: Session ebe2212a hit context limit on EVERY operation for 2+ consecutive reads. Even a single file read triggered the 2013 token limit. The session became completely unusable — every tool call (file read, Edit, Bash) failed with the same error. Had to DELETE the session. Previous session 34967f2c also hit it. This suggests the underlying tmux session accumulates context and eventually becomes permanently exhausted. Pattern: happens after ~10-15 minutes of work or ~10-20 tool calls.