Legal Brain Agent
Ask Japan's legal corpus — statutes, case law, guidelines and legal books — from an AI agent, with citations. One tool, ask_legalbrain, which is a passthrough to Bengo4.com's own legal AI agent. OAuth sign-in, one scope.
Verified connector
Listed by Anthropic as a partner connector in its Connectors Directory.
Connection checked by Agentman on .
Anthropic states this reflects the level of review a connector received, not a security audit.
Connect Legal Brain Agent via MCP
https://api.legalbrain.com/v1/mcpWorks in any MCP-compatible client. In Agentman Studio it is one click — no config file to edit.
Use in Agentman
Connect Legal Brain Agent once and your agents call these tools on their own — on a schedule, in a workflow, with nobody at the keyboard.
Open in Agentman StudioLegal Brain Agent Tools & Capabilities (1)
Tool names from Anthropic's directory listing. This server requires sign-in, so we could not read tool descriptions or parameter schemas.
Limits
- You may not send a real matter. Bengo4.com's terms bar party names, case names and other matter-identifying facts, bar personal and confidential information, and state the service cannot produce specific text for contentious cases. That excludes most live client work by the vendor's own rule.
- The vendor disclaims the accuracy of the output. The terms warrant nothing about fitness, legality, accuracy, usefulness or currency of generated text or search results, and place the duty to verify on the user. They also state the service provides no legal opinion and replaces no professional.
- It is a Japanese-law product with a Japanese interface. Every vendor document we found is in Japanese, and the corpus described is Japanese statutes, precedents, guidelines and books. Nothing suggests coverage of another jurisdiction.
- Bengo4.com publishes no connector documentation. The
documentation,supportandprivacy_policyfields in Anthropic's directory all point at the same Tayori form, whose visible heading is "コネクタ機能 サポート窓口" — a support desk for the connector feature. It is a contact form, not a document: 13 characters of visible text, no mention of MCP or Claude. So the vendor operates a channel for connector questions and publishes no page answering them. Everything on this page comes from the product's terms, privacy policy, external-services list and press material instead. - We never read a live tool list. The endpoint returned HTTP 401 to every anonymous method we tried on 2026-09-09, including a syntactically valid junk bearer token, which returned a byte-identical body. So
ask_legalbrain's parameters, output schema and safety annotations are unknown to us. - The usage cap is contractual and unpublished. The terms make it a term of each individual contract. Pricing is not published anywhere we could reach.
- Output is licensed for internal use only. Publishing it, transmitting it publicly, or profiting from it — including by using the service as an external API — is prohibited by the terms, which provide for disgorgement of any profit made.
- Bengo4.com's corporate site was unreachable to us.
www.bengo4.comreturned HTTP 403 from an Akamai edge to every client we tried, including forrobots.txtitself, so we could not read the vendor's own product page or check its crawl policy. That is a block on our client, not a statement of the vendor's wishes, and we record it as an unknown rather than as a refusal.
Frequently asked questions
Nothing in the published surface writes to a record you own. Anthropic's directory lists one tool, and the OAuth grant carries one scope named after it. But the reach is not read-only in the sense that matters: your prompt is sent to Bengo4.com, and its terms assign the company copyright in both your question and the generated answer. Treat it as a disclosure, not a lookup.
Both, according to Bengo4.com. Its terms define the service as presenting relevant content — statutes, legal issues, court precedents and reference lists — and then supplying prose generated from that content, which the terms name separately as seibun shou. Its June 2026 announcement states every answer displays citations to primary sources. Verify the citations rather than the prose.
No. Bengo4.com's terms prohibit it in two separate clauses. Users must not enter party names, case names or other details identifying a specific matter, and must not enter personal or confidential information belonging to themselves or a third party. The terms also state the service cannot handle contentious or disputed cases. This is the single most consequential limit on the connector.
No, and Bengo4.com says so directly. Its terms state the service does not provide legal opinions and does not substitute for any service supplied by an attorney, tax accountant, judicial scrivener, patent attorney or other legal professional. The same clause disclaims fitness, legality, accuracy, usefulness and currency, and requires the user to verify every output before relying on it.
Not individuals. Bengo4.com's terms restrict applications to corporations including law firms, to partnerships or other organisations, to attorneys, and to anyone the company approves case by case. It also reserves the right to refuse an application on creditworthiness. So a solo consumer cannot sign up, and the connector is unusable without an approved account behind it.
Yes, but the number is not public. Bengo4.com's terms state that a user exceeding the number of uses set in their individual contract may have the service restricted. The cap therefore lives in each customer's own agreement rather than on a published pricing page, so ask your account contact for your figure. No per-call rate limit is documented anywhere.
Anthropic's directory lists one, ask_legalbrain. The endpoint returned HTTP 401 to our anonymous request on 2026-09-09, so we read no live tool list and have no schema, description or safety annotation of our own. The server's OAuth descriptor independently publishes a single scope with the same name, which corroborates the count without confirming it.
No. Bengo4.com's terms restrict generated text to internal use or a scope it approves individually, and prohibit profiting by publishing, publicly transmitting or using the service as an external API. The terms also assign the company copyright in your questions and its answers, and separately prohibit using the service to train AI models.
Sources
- Anthropic Connectors Directory entry, including the description, the single tool name, the endpoint and the partner tier (snapshot dated 2026-09-08). Bengo4.com's directory entry publishes no slug, so this page's URL name was chosen by Agentman. · retrieved 2026-09-08
- LegalBrain エージェント terms of service, in force 2025-05-23 (fetched 2026-09-09; the source of the Content/Generated Text split, the prohibition on matter-identifying and confidential input, the not-legal-advice statement, the eligibility restriction, the usage cap, the copyright assignment and the internal-use limit) · retrieved 2025-05-23
- LegalBrain エージェント privacy policy, in force 2025-05-23 (fetched 2026-09-09; data collected, reuse for marketing and statistics, joint use across Bengo4.com and its subsidiaries) · retrieved 2025-05-23
- LegalBrain エージェント external services and models list, stated as accurate at 2025-07-29 (fetched 2026-09-09; Amazon Bedrock, Anthropic Claude, Cohere Rerank, Google Gemini) · retrieved 2025-07-29
- Bengo4.com press release, "弁護士ドットコム、「LegalBrain エージェント」をアップグレードし、日本初の統合型・法務AIエージェントへ", announced 2026-06-22 for a 2026-06-29 launch (fetched 2026-09-09; the LegalGraph corpus description and the citations-on-every-answer claim) · retrieved 2026-06-22
- Anonymous MCP probe against
https://api.legalbrain.com/v1/mcp— HTTP 401 with aWWW-Authenticate: Bearerchallenge namingresource_metadata, oninitialize,tools/listandDELETEalike; a junk bearer token returned a byte-identical body (2026-09-09). No tool list read. · retrieved 2026-09-09 - LegalBrain RFC 9728 protected-resource metadata (fetched 2026-09-09;
scopes_supported: ["ask_legalbrain"], authorization serverhttps://account.legalbrain.com). An invented path under the same prefix returned HTTP 404, so the descriptor discriminates. · retrieved 2026-09-09 - LegalBrain authorization-server metadata (fetched 2026-09-09; authorization, token, revocation and device-authorization endpoints) · retrieved 2026-09-09
- LegalBrain product site (fetched 2026-09-09;
robots.txtallows all agents. Its sitemap indexes 13 customer case studies and one home page; no MCP or Claude mention anywhere on the host) · retrieved 2026-09-09 - Connector support form named as
documentation,supportandprivacy_policyin Anthropic's directory —https://legalbrain.tayori.com/form/99a79c9756e8663057f5bc1e43fc999b482c1b5b(fetched 2026-09-09; HTTP 200, a Tayori contact form headed "コネクタ機能 サポート窓口", 13 characters of visible text, no MCP or Claude mention) · retrieved 2026-09-09 - Routes that yielded nothing, recorded because the absence is part of the finding:
www.bengo4.com(HTTP 403, Akamai edge,robots.txtrefused too),api.legalbrain.com/(404),legalbrain.com/llms.txt(404),research.legalbrain.com/llms.txt,/robots.txtand/sitemap.xml(all served the app shell, not the file),www.legalbrain.jpandlegal-brain.jp(DNS failure) — all checked 2026-09-09 · retrieved 2026-09-09 - Vendor — Bengo4.com, Inc.,
Server Info
- Category
- Productivity
- Developer
- Legal Brain Agent
- Tools
- 1
- Domain
- api.legalbrain.com
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