Why is it important to specify an exact model version (e.g., claude-sonnet-4-5) rather than an alias (e.g., claude-sonnet-latest) in production applications?
Select an answer to reveal the explanation.
Short Explanation
Pinning to an exact model version is like pinning a dependency version in code. When 'latest' updates, your app behavior can change unexpectedly. Specific versions give you stability.
Full Explanation
Anthropic periodically updates models and may update what 'latest' or similar aliases point to. If your production application uses an alias, a model update could change response patterns, formatting, capabilities, or safety behaviors without warning, potentially breaking your application or evaluation benchmarks. Pinning to a specific version ID, such as claude-sonnet-4-5-20251022, ensures reproducibility. This is standard software engineering practice: pin versions in production, test with new versions before migrating. The claim that specific version strings are cheaper than aliases is wrong because pricing is model-based, not alias versus version. The claim that aliases do not exist in the Anthropic API is wrong because Anthropic does provide convenient aliases. The claim that specific versions have higher rate limits than alias-based requests is wrong because rate limits are account-based, not affected by this.