diff --git a/supabase/migrations/00022_task_id_map.sql b/supabase/migrations/00022_task_id_map.sql
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+-- Map FormulaCode's legacy on-disk task identifiers (the strings under
+-- `analysis/tasks.txt` in formula-code/fc-eval, e.g. `pandas_dev-pandas_3`)
+-- to the canonical (owner, repo, issue_number) identity used everywhere
+-- else in the public API (`pull_requests`, `harbor_runs`,
+-- `findings_workload_tradeoff`, etc.).
+--
+-- Why this exists: the legacy task-id format is `{owner_sanitized}_{repo_
+-- sanitized}_{seq_num}` where `seq_num` is a per-run sequence number (NOT
+-- the GitHub issue/PR number) and the sanitization rule for `_` vs `-` is
+-- inconsistent across rows in `tasks.txt`. Anyone consuming an
+-- `analysis/tasks.txt`-style id needs this table to recover the PR's
+-- actual identity and commit SHA.
+--
+-- See formula-code/fc-eval#19 for context; rows are populated by the
+-- `task_id_map` builder in `analysis/export_website_findings.py`.
+
+CREATE TABLE IF NOT EXISTS task_id_map (
+    legacy_task_id          TEXT PRIMARY KEY,        -- e.g. 'pandas_dev-pandas_3'
+    canonical_task_id       TEXT NOT NULL,           -- '{owner}_{repo}_{issue_number}'
+    owner                   TEXT NOT NULL,
+    repo                    TEXT NOT NULL,
+    issue_number            INT  NOT NULL,
+    pr_merge_commit_sha     TEXT,
+    pr_base_sha             TEXT,
+    FOREIGN KEY (owner, repo, issue_number)
+        REFERENCES pull_requests (owner, repo, issue_number)
+);
+
+CREATE INDEX IF NOT EXISTS idx_task_id_map_canonical
+    ON task_id_map (canonical_task_id);
+CREATE INDEX IF NOT EXISTS idx_task_id_map_pr
+    ON task_id_map (owner, repo, issue_number);
+
+-- RLS + anon grant (same pattern as 00021_findings_tables.sql).
+ALTER TABLE task_id_map ENABLE ROW LEVEL SECURITY;
+CREATE POLICY "public_read" ON task_id_map FOR SELECT TO anon USING (true);
+GRANT SELECT ON task_id_map TO anon;