Context: GitHub Metadata Enrichment & Reliability Score
What it is
For each repository-search result whose URL is on github.com, repository_search_tool fetches repository metadata from the GitHub REST API (https://api.github.com/repos/{owner}/{repo}) using the GITHUB_ACCESS_TOKEN environment variable, and computes a reliability_score. This is enrichment layered on top of the SDE backend (see contexts/science-discovery-engine.md) — it is not a separate corpus.
Metadata fetched
stars (stargazers_count), forks (forks_count), watchers (subscribers_count), open issues (open_issues_count), created_at, and pushed_at (last updated). Non-GitHub URLs are not enriched (repository_metadata is empty and reliability_score is null).
The reliability score (the TOOL owns this score)
The reliability_score (0–100) is a weighted average computed by the tool, ported verbatim from akd-ext calculate_reliability_score:
Score = (Age · 0.20) + (Activity · 0.25) + (Stars · 0.25) + (Forks · 0.15) + (History · 0.15)
- Age (20%) — higher for older repos; reaches 100% after 4 years (1460 days).
- Activity (25%) — starts at 100% and drops toward 0% if the repo hasn't been updated in a year.
- Stars (25%) — logarithmic; ~1,000 stars = 100%.
- Forks (15%) — logarithmic; ~500 forks = 100%.
- History (15%) — span between first commit and now; reaches 100% after 4 years.
The score is computed by the tool, not by the agent. The agent consumes it (and the raw metadata) as supporting-only ranking signals — see guardrails/popularity-signals-supporting-only.md.
Important correction (label vs. implementation)
The v1 prompt labels repository_search_tool "NASA-Verified Repository Search." That label is preserved verbatim in agents.md, but the real implementation is SDE code search + GitHub enrichment, NOT a separate NASA-verified repository corpus.
Related tool
tools/repository_search_tool/.