anthropic/claude-opus-5-5 vs gpt-oss-120b

Practical read: anthropic/claude-opus-5-5 reads seven times more context. One API key runs both.

One key routes both. Starter credit covers your first gpt-oss-120b requests, while anthropic/claude-opus-5-5 runs on your own provider key. Switch by changing the model name.

Side by side:

anthropic/claude-opus-5-5 compared with OpenAI: gpt-oss-120b
Attribute	anthropic/claude-opus-5-5 `anthropic/claude-opus-5-5`	gpt-oss-120b `openai/gpt-oss-120b`
Price, 1M in + out	$25.32 Your provider key	$0.21 Weights & Biases, cheapest route
Best for	Long documents
Cached input	Not published	$0.015825/1M to $0.1055/1M
Context window	1M 1,000,000 tokens	131K 131,072 tokens
First token, p50	Measuring	0.48 s via Cerebras
AI IQ	Unrated	IQ 98 #136 on AI IQ
Provider routes	0	24 with failover
Privacy	Varies by provider	Confidential E2EE and zero retention route
Recent route uptime range	not enough data	100.00%
Publisher	Anthropic	OpenAI
Modes	chat messages	chat
More detail	Overview	Overview Pricing Providers

Price adds one million input and one million output tokens on the cheapest route. Prices and speed change: see the monthly reports and run a small eval before you choose a default.

Test both with your agent

Paste this into Claude Code, Cursor or any coding agent.

Compare anthropic/claude-opus-5-5 and gpt-oss-120b in this project through TrustedRouter.

1. Read https://trustedrouter.com/docs/llms.txt
2. Point the OpenAI-compatible client at
   https://api.trustedrouter.com/v1 and read the key from
   TRUSTEDROUTER_API_KEY.
3. Run our eval prompts on anthropic/claude-opus-5-5, then on openai/gpt-oss-120b.
4. Show me cost, latency and quality side by side before changing the default.

import os
from openai import OpenAI

client = OpenAI(
    base_url="https://api.trustedrouter.com/v1",
    api_key=os.environ["TRUSTEDROUTER_API_KEY"],
)
for model in ("anthropic/claude-opus-5-5", "openai/gpt-oss-120b"):
    response = client.chat.completions.create(
        model=model,
        messages=[{"role": "user", "content": "What is the capital of France?"}],
    )
    print(model, response.choices[0].message.content)

for model in anthropic/claude-opus-5-5 openai/gpt-oss-120b; do
  curl https://api.trustedrouter.com/v1/chat/completions \
    -H "Authorization: Bearer $TRUSTEDROUTER_API_KEY" \
    -H "Content-Type: application/json" \
    -d "{\"model\": \"$model\", \"messages\": [{\"role\": \"user\", \"content\": \"What is the capital of France?\"}]}"
done

Your agent will need an API key.

Questions

Which should I use, anthropic/claude-opus-5-5 or OpenAI: gpt-oss-120b?

anthropic/claude-opus-5-5 has the larger context window. gpt-oss-120b has more Credits provider routes. A published Credits price comparison is not available for both models. There is not enough recent probe data to compare speed.

Is anthropic/claude-opus-5-5 or OpenAI: gpt-oss-120b cheaper?

The current cheapest TrustedRouter route is $25.32/1M for anthropic/claude-opus-5-5 and $0.211/1M for OpenAI: gpt-oss-120b. The comparison uses current catalog prices and updates as provider pricing changes.

Is anthropic/claude-opus-5-5 or OpenAI: gpt-oss-120b faster?

Current measured p50 time to first token is not enough data for anthropic/claude-opus-5-5 and 482 ms for OpenAI: gpt-oss-120b. These are routed probe measurements, not vendor-advertised speeds, and update as new samples arrive.

Can I test anthropic/claude-opus-5-5 and OpenAI: gpt-oss-120b with the same API?

Yes. Use the same OpenAI-compatible TrustedRouter base URL and API key, then change only the model id between anthropic/claude-opus-5-5 and openai/gpt-oss-120b. This makes side-by-side evals possible without maintaining two provider integrations.

More comparisons

All comparisons

Try anthropic/claude-opus-5-5 and gpt-oss-120b with one key.

TrustedRouter is useful when you know the model you want, but still need provider rollover, budget limits, usage records, and a prompt path you can verify.

One key routes both. Starter credit covers your first gpt-oss-120b requests, while anthropic/claude-opus-5-5 runs on your own provider key. Switch by changing the model name.