upload_release_asset

Add files like binaries or documentation to GitHub releases for distribution. Specify repository details, release ID, asset name, content type, and base64-encoded content to attach assets to releases.

Instructions

Upload an asset to a GitHub release

Input Schema

TableJSON Schema

Name	Required	Description
`owner`	Yes	Repository owner (username or organization)
`repo`	Yes	Repository name
`release_id`	Yes	The ID of the release
`name`	Yes	The name of the asset
`label`	No	An alternate short description of the asset
`content`	Yes	The content of the asset (base64 encoded)
`content_type`	Yes	The content type of the asset

Implementation Reference

src/operations/releases.ts:188-226 (handler)

The main handler function that implements the upload_release_asset tool logic. It fetches the release upload URL, constructs the final upload URL with parameters, and performs the POST request to upload the base64-encoded asset content.

export async function uploadReleaseAsset(
  github_pat: string,
  owner: string,
  repo: string,
  release_id: number,
  name: string,
  content: string,
  content_type: string,
  label?: string
): Promise<z.infer<typeof ReleaseAssetSchema>> {
  // Get the release to get the upload_url
  const release = await githubRequest(
    github_pat,
    `https://api.github.com/repos/${owner}/${repo}/releases/${release_id}`
  );
  
  const uploadUrl = (release as any).upload_url.replace(
    "{?name,label}",
    ""
  );
  
  const url = new URL(uploadUrl);
  url.searchParams.append("name", name);
  if (label) url.searchParams.append("label", label);
  
  const response = await githubRequest(
    github_pat,
    url.toString(),
    {
      method: "POST",
      body: Buffer.from(content, "base64").toString(),
      headers: {
        "Content-Type": content_type,
      },
    }
  );
  
  return ReleaseAssetSchema.parse(response);
}

src/operations/releases.ts:102-114 (schema)

Zod schemas defining the input parameters for the upload_release_asset tool. UploadReleaseAssetSchema for public inputs, _UploadReleaseAssetSchema extends it internally with github_pat.

export const UploadReleaseAssetSchema = z.object({
  owner: z.string().describe("Repository owner (username or organization)"),
  repo: z.string().describe("Repository name"),
  release_id: z.number().describe("The ID of the release"),
  name: z.string().describe("The name of the asset"),
  label: z.string().optional().describe("An alternate short description of the asset"),
  content: z.string().describe("The content of the asset (base64 encoded)"),
  content_type: z.string().describe("The content type of the asset")
});

export const _UploadReleaseAssetSchema = UploadReleaseAssetSchema.extend({
  github_pat: z.string().describe("GitHub Personal Access Token"),
});

src/index.ts:184-188 (registration)

Tool registration in the MCP server's listTools handler, defining the tool name, description, and input schema.

{
  name: "upload_release_asset",
  description: "Upload an asset to a GitHub release",
  inputSchema: zodToJsonSchema(releases.UploadReleaseAssetSchema),
},

src/index.ts:567-576 (registration)

Dispatch/registration logic in the CallToolRequest handler's switch statement, parsing arguments and calling the uploadReleaseAsset function.

case "upload_release_asset": {
  const args = releases._UploadReleaseAssetSchema.parse(params.arguments);
  const { github_pat, owner, repo, release_id, name, content, content_type, label } = args;
  const result = await releases.uploadReleaseAsset(
    github_pat, owner, repo, release_id, name, content, content_type, label
  );
  return {
    content: [{ type: "text", text: JSON.stringify(result, null, 2) }],
  };
}

mcp-github