Hermes Agent Integration with LongCat-2.0 (Official Documentation + Nous Portal Free Entry)

One-sentence takeaway

Two commands connect Hermes Agent (Nous Research's open-source terminal Agent) to LongCat-2.0, and the official source offered a free one-week trial on Nous Portal, making it suitable for trying long-running Agents with a 1M context at no cost.

Use cases

• Suitable tasks: Run automated tasks, terminal interactions, and cross-session persistent-memory Agents with Hermes Agent; use LongCat-2.0 as a free or low-cost backend for long-running projects

• Unsuitable tasks: Single-turn conversations that do not need an Agent framework (use the official web chat or API instead); native Windows environments (Hermes requires WSL2)

• Applicable model version: LongCat-2.0 (currently the only model sold on the API platform)

• Applicable clients, Agents, or APIs: Hermes Agent (Linux / macOS / WSL2); Nous Portal (free-quota entry point connected to the OpenRouter channel)

• Recommended reasoning tier and parameters: model.provider must be set to custom; base_url must point to the OpenAI-compatible endpoint; note that Hermes reasoning effort supports only low/med/high (see Bug Report 06 in the reviews directory)

Ready-to-use content

1. Install Hermes Agent

curl -fsSL https://raw.githubusercontent.com/NousResearch/hermes-agent/main/scripts/install.sh | bash
source ~/.bashrc   # or source ~/.zshrc
hermes --version   # the installation succeeded if a version number is printed

2. Configure LongCat (Method A: command line)

hermes config set model.provider custom
hermes config set model.base_url https://api.longcat.chat/openai/v1
hermes config set model.api_key <Your LongCat API Key>
hermes config set model.default LongCat-2.0

3. Configure LongCat (Method B: edit ~/.hermes/config.yaml directly)

model:
  provider: custom
  base_url: https://api.longcat.chat/openai/v1
  api_key: <Your LongCat API Key>
  default: LongCat-2.0

4. Verify and launch

hermes doctor        # check the configuration
hermes               # classic CLI mode
hermes --tui         # modern TUI mode

5. Nous Portal free entry (official announcement)

• On 2026-08-13, Nous Research announced that LongCat-2.0 would be free to use on Nous Portal for one week; entry point: https://portal.nousresearch.com.

• On the Nous Portal model directory (collected 2026-08-18), two entries were available at the same time:

  • Meituan: LongCat 2.0 — IN $0.24 / OUT $0.96 per 1M (OpenRouter paid version, model ID meituan/longcat-2.0-20260720)

  • Meituan: LongCat 2.0 — $0.00/1M (OpenRouter free version, model ID meituan/longcat-2.0:free)

• The free week has ended (it was a one-week trial), but OpenRouter's :free endpoint still showed $0.00 on the collection date.

Raw data and verification notes

• The configuration commands and config.yaml contents were transcribed verbatim from the official documentation (collected on 2026-08-18).

• The Nous Portal free entry was confirmed by official posts from both @NousResearch and @Meituan_LongCat (post IDs are listed above).

• A user test in r/hermesagent (late July 2026) confirmed that this configuration path works and reported a compatibility bug: if Hermes's reasoning effort is set to a tier LongCat does not accept (such as xhigh), LongCat returns a malformed 200 response, causing Hermes to fall back to the fallback provider. The official source has confirmed this issue (see the document in the reviews directory, Bug Report 06).

Scope and limitations

• The free entry's quota, validity period, and rate limits are subject to the real-time Nous Portal / OpenRouter pages; the $0.00 observed on the collection date does not mean it will remain free.

• Model behavior on the official direct channel (api.longcat.chat) and on the Nous Portal/OpenRouter channel (such as cache billing and the default thinking-mode setting) may not be fully consistent.

• Hermes reasoning effort and LongCat's thinking parameter are separate concepts; take care not to conflate them in light of the bug described above.