Use this tool when the user asks about one researcher — 'how much NIH funding does Dr. X have', 'list this PI's grants', 'who does she collaborate with'. Run search_grants (or the find-pi-funding prompt) first: profile_id is the NIH RePORTER PI identifier carried in each result's pi_profile_id field and is not guessable. Read-only PI profile: grants, collaborators, publications, funding totals; the headline name/institution follow the PI's LATEST grant. A fiscal-year window with no grants returns the profile with total_grants=0, not an error. fiscal_year_start/fiscal_year_end scope EVERY aggregate section — grants, profile totals AND collaborators all report only that window (issue #342; collaborators previously ignored it and returned the all-time list). COLLABORATOR COVERAGE, read this before concluding a PI has no collaborators: the collaborator sidecar covers only SOME fiscal years, so an empty collaborators list can mean 'unknown for these years' rather than 'none'. meta.collaborator_coverage.window_covered tells you which: false = no data for any year in the window, and true with window_fully_covered=false means PARTIAL coverage; read missing_fiscal_years_in_window before treating an empty list as a complete answer. fiscal_years_with_collaborator_data lists the years that do have it. Bounds: profile_id 1-20 digits (^[0-9]{1,20}$), fiscal years 1985-2100, limit 1-50 (default 20), offset 0-100000.