Update prompt rule to constrain future event dates and implausible birth dates

[sptrp]

Summary
My first generated article was about the event from the 2029, so this PR updates the prompt rule string used for Halupedia article generation. The change is prompt-only and does not modify generation flow, streaming behavior, validation, or request structure.

What changed

• Updated the rule text in the prompt.
• Added guidance that completed events must not be dated later than today.
• Added guidance that biography/personalia birth dates must be reasonably in the past and not implausibly recent.

Summary by CodeRabbit

• Improvements
  • Articles now reliably conclude cleanly and remain within length limits.
  • Generated content avoids presenting unconfirmed future events as completed facts, reframing them appropriately.
  • Date handling anchors output to a provided "today" value to prevent future-dated assertions.
  • Biography guidance strengthened to ensure subjects’ birth dates are clearly positioned in the past.

[coderabbitai]

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• src/worker/llm.ts

🚧 Files skipped from review as they are similar to previous changes (1)

• src/worker/llm.ts

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📝 Walkthrough

Walkthrough

SYSTEM_PROMPT gains TODAY_UTC-aware output constraints (end cleanly within 350–650 words; no completed events after TODAY_UTC; biography birth dates must be before TODAY_UTC). buildUserMessage now computes TODAY_UTC (ISO YYYY-MM-DD) and prepends it to the user prompt.

Changes

LLM System Prompt Rules

Layer / File(s)	Summary
System prompt constraints src/worker/llm.ts	SYSTEM_PROMPT constant expanded with RULES: articles must "end cleanly" within 350–650 words; TODAY_UTC is the effective current date; completed events dated after TODAY_UTC must be reframed as proposals/rehearsals/admin plans/forecasts/clerical errors; biography/personal subjects' birth dates must be sufficiently in the past relative to TODAY_UTC.
User message date injection src/worker/llm.ts	buildUserMessage(opts) computes TODAY_UTC from now (ISO YYYY-MM-DD) and injects a leading TODAY_UTC: <date> line into the user prompt prior to the article instruction.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Poem

A rabbit types by lantern's light,
Tucks today's date before the write,
No future "done" may slip inside,
Birthdays set where truths abide,
Hopping prompts to keep time right. 🐇✨

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately and concisely summarizes the main changes: updating prompt constraints for future event dates and birth dates.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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[coderabbitai]

Actionable comments posted: 1

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• src/worker/llm.ts

[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@src/worker/llm.ts`:
- Around line 21-25: Remove the duplicate incomplete function declaration that
begins with "export function buildUserMessage(opts: GenerateOptions): string {"
and the partial body that initializes the `lines` array (the broken second
declaration that interrupts the file), so the file only contains the complete,
correct buildUserMessage implementation; ensure the existing `export interface
GenerateOptions` (and any subsequent declarations) remain intact and compile
cleanly after deletion.

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Configuration used: defaults

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📥 Commits

Reviewing files that changed from the base of the PR and between 5a75555 and 92111fb.

📒 Files selected for processing (1)

• src/worker/llm.ts

[BaderBC]

Some people liked that it was mentioning XX century, but I also would like to see your prompt in action.

Let's think about using Math.random to randomly either ask ai for XX century article or present one.

[sptrp]

Some people liked that it was mentioning XX century, but I also would like to see your prompt in action.

Let's think about using Math.random to randomly either ask ai for XX century article or present one.

Some people liked that it was mentioning XX century, but I also would like to see your prompt in action.

Let's think about using Math.random to randomly either ask ai for XX century article or present one.

Hey, @BaderBC thanks for the feedback! Not Sure about whether it should be XX or not, but my issue was that the generated article was describing something which happened in 2029, which cannot happen by all means :) My proposal was about limiting the "happened" events to the present or the past...

[sptrp]

@BaderBC

https://halupedia.com/2029-brazilian-revolution

[HaplessIdiot]

awesome something valid in the PR list this is a major fix thanks a ton hopefully it gets merged