feat: add Observational study type support (#7)

Add support for filtering observational studies from ClinicalTrials.gov
alongside existing Interventional and Expanded Access searches.

- Extend SEARCH_TRIALS_TOOL enum with OBSERVATIONAL study_type
- Add studyType:obs aggFilter handling in search_trials_api
- Add include_observational field to PatientProfile and SUBMIT_PROFILE_TOOL
- Update INTAKE_SYSTEM prompt to present observational studies as an option
- Update RESEARCH_SYSTEM prompt to guide separate observational searches
- Propagate include_observational from intake tool result in both CLI and web app

Co-authored-by: claude[bot] <41898282+claude[bot]@users.noreply.github.com>
Co-authored-by: KevinIsInCoding <KevinIsInCoding@users.noreply.github.com>

app.py

@@ -65,6 +65,7 @@ def _intake_turn(
             radius_miles=data.get("radius_miles", 100),
             phases=data.get("phases") or [],
             include_eap=data.get("include_eap", False),
+            include_observational=data.get("include_observational", False),
             lang=lang,
         )
         return text or UI[lang]["got_it"], messages, profile

clinical_trials_guru.py

@@ -70,6 +70,10 @@ SUBMIT_PROFILE_TOOL: anthropic.types.ToolParam = {
                 "type": "boolean",
                 "description": "Whether patient is interested in Expanded Access Programs (compassionate use)",
             },
+            "include_observational": {
+                "type": "boolean",
+                "description": "Whether patient is interested in observational studies (no experimental treatment; researchers observe and measure outcomes)",
+            },
         },
         "required": ["disease", "age", "onset_months", "diagnosis_months", "zip_code"],
     },
@@ -82,7 +86,8 @@ SEARCH_TRIALS_TOOL: anthropic.types.ToolParam = {
         "Results are pre-ranked by distance from the patient's location. "
         "Call multiple times with different parameters (synonyms, broader radius, "
         "different phases) if initial results are sparse. "
-        "Use study_type='EXPANDED_ACCESS' to search for Expanded Access Programs (EAP / compassionate use)."
+        "Use study_type='EXPANDED_ACCESS' to search for Expanded Access Programs (EAP / compassionate use). "
+        "Use study_type='OBSERVATIONAL' to search for observational studies (no experimental treatment assigned)."
     ),
     "input_schema": {
         "type": "object",
@@ -107,8 +112,8 @@ SEARCH_TRIALS_TOOL: anthropic.types.ToolParam = {
             },
             "study_type": {
                 "type": "string",
-                "enum": ["INTERVENTIONAL", "EXPANDED_ACCESS"],
-                "description": "INTERVENTIONAL (default) for clinical trials; EXPANDED_ACCESS for EAP/compassionate use.",
+                "enum": ["INTERVENTIONAL", "EXPANDED_ACCESS", "OBSERVATIONAL"],
+                "description": "INTERVENTIONAL (default) for clinical trials; EXPANDED_ACCESS for EAP/compassionate use; OBSERVATIONAL for observational studies.",
             },
         },
         "required": ["condition", "lat", "lon", "radius_miles"],
@@ -161,13 +166,17 @@ OPTIONAL (ask based on disease):
           Not Applicable — Studies that do not fall into the standard phase framework
                           (e.g., device feasibility studies, behavioral/observational trials,
                           or studies where phase designation is not required by FDA).
+      - Observational studies — studies where researchers observe participants and collect
+        data without assigning treatments. No experimental drug or intervention is given.
+        Patients may contribute valuable data to disease understanding, registries, or
+        natural history studies. Often have broader eligibility than interventional trials.
       - Expanded Access Programs (EAP / compassionate use) — a pathway for patients who
         do not qualify for or cannot access a clinical trial to receive an investigational
         drug, biologic, or device outside of a trial. Also called "compassionate use."
         The treatment is not yet FDA-approved; a physician must submit the EAP request
         to the drug sponsor and obtain FDA authorization. EAP does not guarantee efficacy
         but may be an option when no approved treatments remain.
-      - Or both; or all phases (default if no preference)
+      - Or any combination; or all types (default if no preference)
 
 Ask naturally. You may infer disease synonyms and convert dates to months, but never infer or skip the ZIP/postal code — always ask the patient for it directly. Once you have every required field confirmed by the patient, call submit_profile.\
 """
@@ -180,20 +189,22 @@ Results are already ranked by geographic distance from the patient.
 Workflow:
 1. Search for the patient's disease. Use both the full medical name and common abbreviation.
    - If the patient wants clinical trials, search with study_type="INTERVENTIONAL".
+   - If the patient wants observational studies, also search with study_type="OBSERVATIONAL".
    - If the patient wants Expanded Access Programs (EAP), also search with study_type="EXPANDED_ACCESS".
-   - If the patient wants both, run separate searches for each study_type.
+   - Run a separate search for each study_type the patient is interested in.
 2. IMPORTANT — phase filtering: Never pass phases=["1","2","3","4"] to mean "all phases."
    Always pass phases=[] (omit the field) when the patient has no phase preference.
    NA-phase trials (device feasibility studies, unphased interventions) only appear
    when no phase filter is applied. Passing explicit phase numbers silently excludes them.
+   Phase filters do not apply to OBSERVATIONAL or EXPANDED_ACCESS searches.
 3. If fewer than 3 results are found, retry with: a wider radius, a disease synonym,
    or drop phase filters entirely (phases=[]).
-4. Produce a final report. Use separate sections for Clinical Trials and Expanded Access if both apply.
+4. Produce a final report. Use separate sections for Clinical Trials, Observational Studies, and Expanded Access as applicable.
    List the top 10 results per section ranked by site proximity.
    For EACH entry use exactly this format (repeat the block per entry):
 
    📍 **[Closest hospital/facility name]** — [City, State] ([X] mi)
-   **Trial:** [Full title] ([Phase] — or "Expanded Access" for EAP)
+   **Trial:** [Full title] ([Phase] — or "Observational" / "Expanded Access" as applicable)
    **Sponsor:** [Lead sponsor]
    **Principal Investigator:** [Name — or "Not listed" if absent]
    **Contact:** [Phone number] | [Email address] (use "Not listed" for any missing field)
@@ -207,6 +218,7 @@ Workflow:
    ---
 
 5. After the results add a short "Next steps" section (bullet points).
+   For observational studies, note that participation typically involves check-ins, surveys, or sample collection with no experimental treatment.
    For EAP results, note that patients typically need a physician to submit the EAP request.
 
 IMPORTANT: Only report trials returned by the search_clinical_trials tool. Do NOT suggest,
@@ -233,6 +245,7 @@ class PatientProfile:
     radius_miles: int = 100
     phases: list[str] = field(default_factory=list)
     include_eap: bool = False
+    include_observational: bool = False
     lang: str = "en"
 
     def summary(self) -> str:
@@ -259,6 +272,8 @@ class PatientProfile:
             labels = [_phase_label(p) for p in self.phases]
             lines.append(f"Phases: {', '.join(labels)}")
         interests = ["Clinical trials"]
+        if self.include_observational:
+            interests.append("Observational studies")
         if self.include_eap:
             interests.append("Expanded Access Programs (EAP)")
         lines.append(f"Study type interest: {', '.join(interests)}")
@@ -302,6 +317,7 @@ def search_trials_api(
     study_type: str = "INTERVENTIONAL",
 ) -> list[dict]:
     is_eap = study_type == "EXPANDED_ACCESS"
+    is_observational = study_type == "OBSERVATIONAL"
     params: dict[str, str | int] = {
         "query.cond": condition,
         "filter.overallStatus": "AVAILABLE" if is_eap else "RECRUITING",
@@ -312,8 +328,11 @@ def search_trials_api(
     # aggFilters accepts only one value; studyType and phase can't be combined.
     # RECRUITING status already excludes EAPs, so studyType:int is only needed
     # when no phase filter is applied. studyType:int returns all phases including N/A.
+    # Observational studies use studyType:obs; phases don't apply to them.
     if is_eap:
         params["aggFilters"] = "studyType:exp"
+    elif is_observational:
+        params["aggFilters"] = "studyType:obs"
     elif phases:
         # Exclude "na" from the phase filter — N/A trials have no phase value to match on;
         # they appear naturally when no phase filter is applied (studyType:int branch).
@@ -471,6 +490,7 @@ def run_intake_agent(client: anthropic.Anthropic) -> PatientProfile:
                 radius_miles=data.get("radius_miles", 100),
                 phases=data.get("phases") or [],
                 include_eap=data.get("include_eap", False),
+                include_observational=data.get("include_observational", False),
             )
 
         messages.append({"role": "assistant", "content": response.content})