Skip to content

[BOT ISSUE] Anthropic: add missing claude-mythos-5 (re-removed by sync) #1249

Closed
#1250
Closed
[BOT ISSUE] Anthropic: add missing claude-mythos-5 (re-removed by sync)#1249
#1250

Description

@github-actions
github-actions
bot
opened on Sep 15, 2026

Summary

Claude Mythos 5 (claude-mythos-5) and its Bedrock variants are confirmed on the Anthropic model page and pricing page but are absent from packages/proxy/schema/model_list.json. The parallel model claude-fable-5 (same pricing, same generation) is in the catalog at line ~8524.

Sync issue: This model has been filed 3 times before (#814, #982, #1049), each closed as completed, but the model was removed by the LiteLLM sync process each time. To prevent removal, these model IDs should be added to SYNC_PRESERVED_FIELDS in packages/proxy/scripts/sync_models.ts, or the sync script should be updated to preserve them.

Missing Model IDs

Model ID Surface Input $/MTok Output $/MTok Cache Read $/MTok Context Max Output
claude-mythos-5 Anthropic API $10.00 $50.00 $1.00 1,000,000 128,000
anthropic.claude-mythos-5 Bedrock $10.00 $50.00 $1.00 1,000,000 128,000
global.anthropic.claude-mythos-5 Bedrock (global) $10.00 $50.00 $1.00 1,000,000 128,000

Suggested Catalog Entries

"claude-mythos-5": {
  "format": "anthropic",
  "flavor": "chat",
  "multimodal": true,
  "input_cost_per_mil_tokens": 10,
  "output_cost_per_mil_tokens": 50,
  "input_cache_read_cost_per_mil_tokens": 1,
  "input_cache_write_cost_per_mil_tokens": 12.5,
  "input_cache_write_5m_cost_per_mil_tokens": 12.5,
  "input_cache_write_1h_cost_per_mil_tokens": 20,
  "displayName": "Claude Mythos 5",
  "reasoning": true,
  "reasoning_budget": true,
  "deprecation_date": "2027-06-09",
  "fallback_models": [
    "anthropic.claude-mythos-5",
    "global.anthropic.claude-mythos-5"
  ],
  "max_input_tokens": 1000000,
  "max_output_tokens": 128000,
  "available_providers": [
    "anthropic"
  ]
}
"anthropic.claude-mythos-5": {
  "format": "anthropic",
  "flavor": "chat",
  "multimodal": true,
  "input_cost_per_mil_tokens": 10,
  "output_cost_per_mil_tokens": 50,
  "input_cache_read_cost_per_mil_tokens": 1,
  "input_cache_write_cost_per_mil_tokens": 12.5,
  "displayName": "Claude Mythos 5",
  "reasoning": true,
  "reasoning_budget": true,
  "max_input_tokens": 1000000,
  "max_output_tokens": 128000,
  "available_providers": [
    "bedrock"
  ]
}
"global.anthropic.claude-mythos-5": {
  "format": "anthropic",
  "flavor": "chat",
  "multimodal": true,
  "input_cost_per_mil_tokens": 10,
  "output_cost_per_mil_tokens": 50,
  "input_cache_read_cost_per_mil_tokens": 1,
  "input_cache_write_cost_per_mil_tokens": 12.5,
  "displayName": "Global Claude Mythos 5",
  "reasoning": true,
  "reasoning_budget": true,
  "parent": "anthropic.claude-mythos-5",
  "max_input_tokens": 1000000,
  "max_output_tokens": 128000,
  "available_providers": [
    "bedrock"
  ]
}

Entry structures mirror the existing claude-fable-5 / anthropic.claude-fable-5 / global.anthropic.claude-fable-5 entries.

Sync Preservation Required

This model has been added and removed by sync 3 times (see issues #814, #982, #1049). To persist the fix, add these model IDs to SYNC_PRESERVED_FIELDS in packages/proxy/scripts/sync_models.ts with all cost-related fields preserved, similar to how grok models are handled.

Verification Checklist

Check Status Detail
Cross-source ✅ Confirmed on Anthropic Model Page (API ID, Bedrock ID, specs) AND Anthropic Pricing (per-token pricing, cache rates, batch pricing)
Already in catalog ✅ grep claude-mythos-5 model_list.json returns zero matches on current main (commit cba1919)
ID format ✅ Follows existing convention: claude-fable-5 / anthropic.claude-fable-5 / global.anthropic.claude-fable-5
Duplicate issue ✅ No open issue covers claude-mythos-5. Prior issues #814, #982, #1049 all closed — model was added then removed by sync
Not deprecated ✅ Status: Active (invite only). Retirement not sooner than June 9, 2027
Not embedding/vision-only ✅ Multimodal chat model (text + image input, text output)

Verification Notes

Field Source Notes
Model ID claude-mythos-5 Model page Listed as Claude API model ID
Bedrock ID anthropic.claude-mythos-5 Model page Listed in platform IDs table
Pricing $10/$50 Pricing page Row: "Claude Mythos 5 (limited availability)"
Cache read $1/MTok Pricing page Standard 0.1x multiplier (unlike Mythos 5.1 which uses 0.025x)
Cache write 5m $12.50/MTok Pricing page 1.25x base input price
Cache write 1h $20/MTok Pricing page 2x base input price
reasoning: true, reasoning_budget: true Model page "Adaptive thinking (always on)" with default effort high
max_input_tokens: 1000000 Model page 1M token context window
max_output_tokens: 128000 Model page 128K max output
deprecation_date: "2027-06-09" Model page "Retirement: Not sooner than June 9, 2027" — matches claude-fable-5

Prior Issues (all closed, model still missing)

Issue Filed Closed Outcome
#814 2026-06-17 2026-06-18 PR #822 added model; later removed by sync
#982 2026-07-15 2026-07-27 Confirmed model added then removed by sync
#1049 2026-08-01 2026-08-03 Same model, re-filed and closed

Local Files Inspected

  • packages/proxy/schema/model_list.json — confirmed zero matches for claude-mythos-5; claude-fable-5 at line ~8524 used as reference template
  • packages/proxy/scripts/sync_models.ts — claude-mythos-5 not in SYNC_PRESERVED_FIELDS
{
  "kind": "missing_model",
  "provider": "anthropic",
  "models": ["claude-mythos-5", "anthropic.claude-mythos-5", "global.anthropic.claude-mythos-5"],
  "status": "active",
  "model_specs": {
    "claude-mythos-5": {
      "format": "anthropic",
      "flavor": "chat",
      "multimodal": true,
      "input_cost_per_mil_tokens": 10,
      "output_cost_per_mil_tokens": 50,
      "input_cache_read_cost_per_mil_tokens": 1,
      "input_cache_write_cost_per_mil_tokens": 12.5,
      "input_cache_write_5m_cost_per_mil_tokens": 12.5,
      "input_cache_write_1h_cost_per_mil_tokens": 20,
      "displayName": "Claude Mythos 5",
      "reasoning": true,
      "reasoning_budget": true,
      "deprecation_date": "2027-06-09",
      "fallback_models": ["anthropic.claude-mythos-5", "global.anthropic.claude-mythos-5"],
      "max_input_tokens": 1000000,
      "max_output_tokens": 128000,
      "available_providers": ["anthropic"]
    },
    "anthropic.claude-mythos-5": {
      "format": "anthropic",
      "flavor": "chat",
      "multimodal": true,
      "input_cost_per_mil_tokens": 10,
      "output_cost_per_mil_tokens": 50,
      "input_cache_read_cost_per_mil_tokens": 1,
      "input_cache_write_cost_per_mil_tokens": 12.5,
      "displayName": "Claude Mythos 5",
      "reasoning": true,
      "reasoning_budget": true,
      "max_input_tokens": 1000000,
      "max_output_tokens": 128000,
      "available_providers": ["bedrock"]
    },
    "global.anthropic.claude-mythos-5": {
      "format": "anthropic",
      "flavor": "chat",
      "multimodal": true,
      "input_cost_per_mil_tokens": 10,
      "output_cost_per_mil_tokens": 50,
      "input_cache_read_cost_per_mil_tokens": 1,
      "input_cache_write_cost_per_mil_tokens": 12.5,
      "displayName": "Global Claude Mythos 5",
      "reasoning": true,
      "reasoning_budget": true,
      "parent": "anthropic.claude-mythos-5",
      "max_input_tokens": 1000000,
      "max_output_tokens": 128000,
      "available_providers": ["bedrock"]
    }
  },
  "source_urls": [
    "https://platform.claude.com/docs/en/models/mythos-5/overview",
    "https://platform.claude.com/docs/en/about-claude/pricing"
  ]
}

Activity

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Metadata

Metadata

Assignees

No one assigned

    Labels

    No labels
    No labels

    Type

    No type

    Projects

    No projects

      Milestone

      No milestone

      Relationships

      None yet

      Development

      No branches or pull requests

      Issue actions