Claude 1.0

Claude 1.0 launched March twenty twenty-three. First constitutional AI model. Nine thousand context. Superseded by 2/3/3.5/4.x. Historical only — not for production use.

Claude 1.0 was Anthropic's first production model released March twenty twenty-three, introducing constitutional AI training with nine thousand token context, superseded by Claude 2 (100K), 3 (200K), 3.5, and 4.x series — retained for historical benchmarking.

Provider: Anthropic · Family: Claude 1

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Context window: 9,000 tokens

Input modalities: text · Output: text

About Claude 1.0

Claude 1.0 is the founding model of Anthropic's Claude family, released on March 14, 2023 via limited API beta to approved developers. Built on a dense Transformer architecture and trained using Anthropic's Constitutional AI method combined with reinforcement learning from human feedback, Claude 1.0 represented the company's first public deployment of its alignment-centric training philosophy. The model's parameter count was never disclosed, which became a pattern Anthropic maintained across all subsequent generations. Claude 1.0 sat at the entry tier of what would become a multi-generation model lineup, positioned for general text tasks with an explicit safety-first design. Anthropic did not publish formal benchmark results for Claude 1.0 in any model card or technical report. The company's first detailed public benchmarks came with Claude 2 in July 2023, which showed improved scores versus the Claude 1 baseline on HumanEval, GSM8K, and MMLU, without specifying exact Claude 1.0 figures. Independent evaluators at the time noted performance in the GPT-3.5 tier for most text tasks but no exact independently verified numbers exist for MMLU, HumanEval, or reasoning tasks for this model. The absence of published benchmarks aligned with Anthropic's early philosophy of avoiding arms-race comparisons. Claude 1.0 launched with a 9,000-token context window, roughly equivalent to 6,000 to 7,000 words or about 20 to 25 pages of text. This was expanded substantially when Claude v1.3 introduced a 100,000-token context in May 2023, an approximately eleven-fold increase. Anthropic applied the same per-token pricing to both 9K and 100K context tiers at launch. Max output tokens were not separately documented but followed standard dense Transformer generation limits. The original 9K window constrained the model to short-to-medium document processing with no ability to ingest full books, large codebases, or extended conversation histories in a single pass. Claude 1.0 was strictly text-to-text. It accepted text input and produced text output with no support for images, audio, video, or native PDF parsing. Multimodal input capabilities were not introduced until Claude 3 in March 2024. Function calling existed only through structured prompting conventions, not a formal tool use API. The model handled code generation, summarization, translation, and dialogue via text alone. No computer use, file upload, or web browsing was supported natively. Claude 1.0 was priced on a per-token model through the Anthropic API. Exact historical per-million-token rates are no longer published following the model's retirement in November 2024. At launch in 2023, pricing was competitive with GPT-3.5 class models in the market. Anthropic applied the same rate for both 9K and 100K context variants when the context expansion was announced in May 2023, an unusual pricing decision that drew developer attention at the time. No free tier, batch discount, or prompt caching feature existed for Claude 1.0. Access was available only via the Anthropic direct API during the model's operational period. Amazon Bedrock added support for the Claude 1 series during 2023. Authentication required an Anthropic API key. Google Vertex AI and Azure deployments were not available for the Claude 1 family. The API model IDs claude-1.0, claude-1.1, claude-1.2, and claude-1.3 all now return errors, as all four were retired on November 6, 2024. Anthropic announced the deprecation on September 4, 2024 and gave developers 60 days to migrate to claude-2.0 or newer models. Claude 1.0 was trained using Constitutional AI, a method Anthropic published in December 2022. The technique trains the model to critique and revise its own outputs using a written set of guiding principles called a constitution, then fine-tunes on the revised outputs via supervised learning. A reinforcement learning phase follows using AI-generated preference signals rather than purely human-labeled comparisons, making alignment more scalable. Anthropic published its first constitution in May 2023 with 75 principles drawn from the UN Universal Declaration of Human Rights and Apple's terms of service. The model carried a strict safety posture, refusing a wider range of requests than later Claude generations, reflecting Anthropic's conservative alignment defaults during this period. No formal red-teaming partner list was published for Claude 1.0. Claude 1.0 is fully retired and inaccessible via any API endpoint. No active production workload can use this model. Developers who built on the claude-1.0 API model ID were required to migrate before November 6, 2024. The model is of historical interest as the origin of the Claude family and the first commercial deployment of Constitutional AI training but cannot serve any current inference use case. Anthropic has committed to long-term preservation of model weights, so the model may become accessible again in research contexts in the future, but no public timeline exists. Training data for Claude 1.0 consisted of a proprietary mix of publicly available Internet text, licensed third-party datasets, and human-annotated examples. Training data cutoff is estimated at early 2023, consistent with what Anthropic disclosed for Claude 2, its direct successor. Inputs to the API were retained under Anthropic's standard data policy during the model's active period. No SOC 2 Type II, HIPAA, or ISO 27001 certifications were held for the Claude 1 generation; those enterprise compliance tiers were added in later model generations alongside Anthropic's expanding enterprise business.

Pricing

Historical per-token pricing no longer published. Model retired November 6, 2024. No API access available.

Key Features

• Constitutional AI Training: First commercial model trained via Anthropic's Constitutional AI method, using a written set of 75 principles to guide self-critique and revision during training.
• 100K Context (v1.3): Context window expanded from 9,000 to 100,000 tokens with claude-1.3 in May 2023, eleven times the initial limit, at no additional per-token cost.
• Strict Safety Defaults: Wider refusal range than later Claude generations, reflecting Anthropic's conservative alignment posture during the 2023 period of AI development.
• Human/Assistant Prompt Format: Used the original Human/Assistant stop sequence format before the Messages API was introduced, establishing the conversational interface pattern.

Pros

• First deployment of Constitutional AI training in a commercial LLM, establishing alignment practices that all later Claude models built on.
• Context window expanded to 100K tokens in May 2023 via claude-1.3, ahead of GPT-3.5 at the time.
• Strict safety posture produced lower rates of harmful content generation than many GPT-3.5 class contemporaries.

Cons

• Fully retired as of November 6, 2024. No API access is possible under any circumstances.
• No published benchmarks, making capability assessment against contemporaries reliant on informal comparisons only.
• Text-only input with no image, audio, or vision support in any version of the Claude 1 family.

Visit Claude 1.0 Official Page