diff --git a/sharness/__snapshots__/example-github-load/projects/c291cmNlY3JlZC10ZXN0L2V4YW1wbGUtZ2l0aHVi/project.json b/sharness/__snapshots__/example-github-load/projects/c291cmNlY3JlZC10ZXN0L2V4YW1wbGUtZ2l0aHVi/project.json
index 01562ef..cdb4686 100644
--- a/sharness/__snapshots__/example-github-load/projects/c291cmNlY3JlZC10ZXN0L2V4YW1wbGUtZ2l0aHVi/project.json
+++ b/sharness/__snapshots__/example-github-load/projects/c291cmNlY3JlZC10ZXN0L2V4YW1wbGUtZ2l0aHVi/project.json
@@ -1 +1 @@
-[{"type":"sourcecred/project","version":"0.5.0"},{"discourseServer":null,"id":"sourcecred-test/example-github","identities":[],"initiatives":null,"repoIds":[{"name":"example-github","owner":"sourcecred-test"}]}]
\ No newline at end of file
+[{"type":"sourcecred/project","version":"0.5.1"},{"discourseServer":null,"id":"sourcecred-test/example-github","identities":[],"initiatives":null,"repoIds":[{"name":"example-github","owner":"sourcecred-test"}],"timelineCredParams":null}]
\ No newline at end of file
diff --git a/src/analysis/timeline/params.js b/src/analysis/timeline/params.js
index 8ebfea6..180db79 100644
--- a/src/analysis/timeline/params.js
+++ b/src/analysis/timeline/params.js
@@ -62,7 +62,7 @@ export function defaultParams(): TimelineCredParameters {
  * Fill in default values for timeline cred parameters.
  */
 export function partialParams(
-  partial: $Shape<TimelineCredParameters>
+  partial: $Shape<TimelineCredParameters> | null
 ): TimelineCredParameters {
   return {...defaultParams(), ...partial};
 }
diff --git a/src/cli/load.js b/src/cli/load.js
index 4586312..a629401 100644
--- a/src/cli/load.js
+++ b/src/cli/load.js
@@ -6,7 +6,7 @@ import {LoggingTaskReporter} from "../util/taskReporter";
 import type {Command} from "./command";
 import * as Common from "./common";
 import * as Weights from "../core/weights";
-import {projectFromJSON} from "../core/project";
+import {projectFromJSON, type Project} from "../core/project";
 import {load} from "../api/load";
 import {specToProject} from "../plugins/github/specToProject";
 import fs from "fs-extra";
@@ -14,7 +14,7 @@ import {type PluginDeclaration} from "../analysis/pluginDeclaration";
 import {declaration as discourseDeclaration} from "../plugins/discourse/declaration";
 import {declaration as githubDeclaration} from "../plugins/github/declaration";
 import {declaration as identityDeclaration} from "../plugins/identity/declaration";
-import {defaultParams} from "../analysis/timeline/params";
+import {partialParams} from "../analysis/timeline/params";
 
 function usage(print: (string) => void): void {
   print(
@@ -126,7 +126,7 @@ const loadCommand: Command = async (args, std) => {
 
   const taskReporter = new LoggingTaskReporter();
 
-  const specProjects = await Promise.all(
+  const specProjects: $ReadOnlyArray<Project> = await Promise.all(
     projectSpecs.map((s) => specToProject(s, githubToken))
   );
   const manualProjects = await Promise.all(projectPaths.map(loadProject));
@@ -142,9 +142,11 @@ const loadCommand: Command = async (args, std) => {
     if (project.identities.length) {
       plugins.push(identityDeclaration);
     }
+    const params = partialParams(project.timelineCredParams);
+
     return {
       project,
-      params: defaultParams(),
+      params,
       weightsOverrides: weights,
       plugins,
       sourcecredDirectory: Common.sourcecredDirectory(),
diff --git a/src/core/project.js b/src/core/project.js
index 7170087..9c22536 100644
--- a/src/core/project.js
+++ b/src/core/project.js
@@ -6,6 +6,7 @@ import {toCompat, fromCompat, type Compatible} from "../util/compat";
 import {type ProjectParameters as Initiatives} from "../plugins/initiatives/params";
 import {type Identity} from "../plugins/identity/identity";
 import {type DiscourseServer} from "../plugins/discourse/server";
+import type {TimelineCredParameters} from "../analysis/timeline/params";
 
 export type ProjectId = string;
 
@@ -25,22 +26,24 @@ export type ProjectId = string;
  * the future (e.g. showing the last update time for each of the project's data
  * dependencies).
  */
-export type Project = ProjectV050;
+export type Project = ProjectV051;
 export type SupportedProject =
   | ProjectV030
   | ProjectV031
   | ProjectV040
+  | ProjectV051
   | ProjectV050;
 
-export type ProjectV050 = {|
+export type ProjectV051 = {|
   +id: ProjectId,
   +initiatives: Initiatives | null,
   +repoIds: $ReadOnlyArray<RepoId>,
   +discourseServer: DiscourseServer | null,
   +identities: $ReadOnlyArray<Identity>,
+  +timelineCredParams: $Shape<TimelineCredParameters> | null,
 |};
 
-const COMPAT_INFO = {type: "sourcecred/project", version: "0.5.0"};
+const COMPAT_INFO = {type: "sourcecred/project", version: "0.5.1"};
 
 /**
  * Creates a new Project instance with default values.
@@ -57,6 +60,7 @@ export function createProject(p: $Shape<Project>): Project {
     identities: [],
     discourseServer: null,
     initiatives: null,
+    timelineCredParams: null,
     ...p,
   };
 }
@@ -79,11 +83,25 @@ export function encodeProjectId(id: ProjectId): string {
   return base64url.encode(id);
 }
 
-const upgradeFrom040 = (p: ProjectV040): ProjectV050 => ({
+const upgradeFrom050 = (p: ProjectV050): ProjectV051 => ({
   ...p,
-  initiatives: null,
+  timelineCredParams: {},
 });
 
+export type ProjectV050 = {|
+  +id: ProjectId,
+  +initiatives: Initiatives | null,
+  +repoIds: $ReadOnlyArray<RepoId>,
+  +discourseServer: DiscourseServer | null,
+  +identities: $ReadOnlyArray<Identity>,
+|};
+
+const upgradeFrom040 = (p: ProjectV040) =>
+  upgradeFrom050({
+    ...p,
+    initiatives: null,
+  });
+
 export type ProjectV040 = {|
   +id: ProjectId,
   +repoIds: $ReadOnlyArray<RepoId>,
@@ -124,4 +142,5 @@ const upgrades = {
   "0.3.0": upgradeFrom030,
   "0.3.1": upgradeFrom030,
   "0.4.0": upgradeFrom040,
+  "0.5.0": upgradeFrom050,
 };
diff --git a/src/core/project.test.js b/src/core/project.test.js
index e6dc398..08ad85d 100644
--- a/src/core/project.test.js
+++ b/src/core/project.test.js
@@ -15,6 +15,7 @@ import {
 
 import {makeRepoId} from "../plugins/github/repoId";
 import {toCompat} from "../util/compat";
+import type {ProjectV050} from "./project";
 
 describe("core/project", () => {
   const foobar = deepFreeze(makeRepoId("foo", "bar"));
@@ -25,6 +26,7 @@ describe("core/project", () => {
     discourseServer: null,
     initiatives: null,
     identities: [],
+    timelineCredParams: null,
   });
   const p2: Project = deepFreeze({
     id: "@foo",
@@ -37,6 +39,7 @@ describe("core/project", () => {
         aliases: ["github/example"],
       },
     ],
+    timelineCredParams: null,
   });
   describe("to/from JSON", () => {
     it("round trip is identity", () => {
@@ -74,6 +77,7 @@ describe("core/project", () => {
           // It should strip the apiUsername field, keeping just serverUrl.
           discourseServer: {serverUrl: "https://example.com"},
           initiatives: null,
+          timelineCredParams: {},
         }: Project)
       );
     });
@@ -103,6 +107,7 @@ describe("core/project", () => {
           // It should strip the apiUsername field, keeping just serverUrl.
           discourseServer: {serverUrl: "https://example.com"},
           initiatives: null,
+          timelineCredParams: {},
         }: Project)
       );
     });
@@ -128,6 +133,33 @@ describe("core/project", () => {
           ...body,
           // It should add a default initiatives field.
           initiatives: null,
+          timelineCredParams: {},
+        }: Project)
+      );
+    });
+    it("should upgrade from 0.5.0 formatting", () => {
+      // Given
+      const body: ProjectV050 = {
+        id: "example-050",
+        repoIds: [foobar, foozod],
+        discourseServer: {serverUrl: "https://example.com"},
+        identities: [],
+        initiatives: null,
+      };
+      const compat = toCompat(
+        {type: "sourcecred/project", version: "0.5.0"},
+        body
+      );
+
+      // When
+      const project = projectFromJSON(compat);
+
+      // Then
+      expect(project).toEqual(
+        ({
+          ...body,
+          // It should add default params field.
+          timelineCredParams: {},
         }: Project)
       );
     });
@@ -169,6 +201,7 @@ describe("core/project", () => {
         initiatives: null,
         repoIds: [],
         identities: [],
+        timelineCredParams: null,
       });
     });
     it("treats input shape as overrides", () => {
@@ -185,6 +218,7 @@ describe("core/project", () => {
             aliases: ["github/example"],
           },
         ],
+        timelineCredParams: {alpha: 0.2, intervalDecay: 0.5},
       };
 
       // When
diff --git a/src/core/project_io.test.js b/src/core/project_io.test.js
index 9c2cee9..03f972f 100644
--- a/src/core/project_io.test.js
+++ b/src/core/project_io.test.js
@@ -38,6 +38,7 @@ describe("core/project_io", () => {
     discourseServer: {serverUrl: "https://example.com"},
     identities: [{username: "foo", aliases: ["github/foo", "discourse/foo"]}],
     initiatives: {remoteUrl: "https://example.com/initiatives"},
+    timelineCredParams: {alpha: 0.2, intervalDecay: 0.5},
   });
 
   it("setupProjectDirectory results in a loadable project", async () => {