docs(plugin-mcp): recommend HTTP and explain stdio limitations

[AlessioGr]

This PR updates the MCP documentation to recommend HTTP for both local development and production. The docs now mainly recommend the use HTTP. The stdio instructions are kept in one section at the end of the page, together with its current limitations.

It also makes the stdio CLI load .env files before importing the payload config. This matches the normal Payload CLI and allows config values such as PAYLOAD_SECRET to work without adding them separately to the MCP client configuration.

Why?

Stdio is convenient during development because it is simple to configure, can work well in repos with multiple payload configs (like our monorepo), and avoids MCP client connection timeouts or race conditions.

The main drawback is HMR. The stdio process loads the Payload config and MCP registrations once, so changes such as adding a collection or tool normally require a restart. Given stdio would usually be used during development, where these things usually happen, we cannot recommend it in this state. HTTP does not have this problem because it uses the running app’s existing HMR (e.g. Next.js HMR through getPayload).

I attempted to add HMR to the stdio mcp process by using Vite as an optional peer dependency, since Next.js is not available to handle HMR for this standalone process. The reload worked, but keeping the long-running MCP server and its authorization state in sync added too much complexity to the plugin. The attempted fix is preserved on fix/do-not-delete-branch-stdio-hmr if we revisit it. For now, this is not high priority. The stdio mcp remains usable in its current state

[github-actions]

📦 esbuild Bundle Analysis for payload

This analysis was generated by esbuild-bundle-analyzer. 🤖

Meta File	Out File	Size (raw)	Note
packages/next/meta_index.json	esbuild/index.js	201.89 KB	✅ No change
packages/payload/meta_index.json	esbuild/index.js	1.41 MB	⚠️ +4.38 KB (+0.3%)
packages/payload/meta_shared.json	esbuild/exports/shared.js	213.20 KB	✅ -26 B (-0.0%)
packages/richtext-lexical/meta_client.json	esbuild/exports/client_optimized/index.js	285.56 KB	✅ No change
packages/ui/meta_client.json	esbuild/exports/client_optimized/index.js	36.16 KB	✅ No change
packages/ui/meta_shared.json	esbuild/exports/shared_optimized/index.js	18.95 KB	✅ No change

Largest paths

These visualization shows top 20 largest paths in the bundle.

Meta file: packages/next/meta_index.json, Out file: esbuild/index.js

Path	Size
../../node_modules	${{\color{Goldenrod}{ ████████████████████████▋ }}}$ 98.9%, 197.86 KB
dist/adapters/router.js	${{\color{Goldenrod}{ }}}$ 0.4%, 718 B
dist/adapters/server.js	${{\color{Goldenrod}{ }}}$ 0.3%, 533 B
dist/adapters/layout.js	${{\color{Goldenrod}{ }}}$ 0.3%, 526 B
dist/adapters/views.js	${{\color{Goldenrod}{ }}}$ 0.2%, 409 B
dist/esbuildEntry.js	${{\color{Goldenrod}{ }}}$ 0.0%, 0 B

Meta file: packages/payload/meta_index.json, Out file: esbuild/index.js

Path	Size
../../node_modules	${{\color{Goldenrod}{ █████████████████▏ }}}$ 68.8%, 964.37 KB
dist/fields/hooks	${{\color{Goldenrod}{ ▊ }}}$ 3.2%, 44.37 KB
dist/collections/operations	${{\color{Goldenrod}{ ▊ }}}$ 3.0%, 42.69 KB
dist/utilities/configToJSONSchema.js	${{\color{Goldenrod}{ ▎ }}}$ 1.1%, 15.99 KB
dist/auth/operations	${{\color{Goldenrod}{ ▎ }}}$ 1.1%, 15.68 KB
dist/fields/config	${{\color{Goldenrod}{ ▎ }}}$ 1.0%, 13.79 KB
dist/globals/operations	${{\color{Goldenrod}{ ▎ }}}$ 1.0%, 13.36 KB
dist/queues/operations	${{\color{Goldenrod}{ ▏ }}}$ 0.9%, 12.63 KB
dist/fields/validations.js	${{\color{Goldenrod}{ ▏ }}}$ 0.8%, 10.73 KB
dist/bin/generateImportMap	${{\color{Goldenrod}{ ▏ }}}$ 0.7%, 9.84 KB
dist/collections/config	${{\color{Goldenrod}{ ▏ }}}$ 0.7%, 9.30 KB
dist/config/orderable	${{\color{Goldenrod}{ ▏ }}}$ 0.6%, 8.07 KB
dist/index.js	${{\color{Goldenrod}{ ▏ }}}$ 0.6%, 7.96 KB
dist/uploads/fetchAPI-multipart	${{\color{Goldenrod}{ ▏ }}}$ 0.6%, 7.84 KB
dist/hierarchy/utils	${{\color{Goldenrod}{ ▏ }}}$ 0.5%, 7.64 KB
dist/database/migrations	${{\color{Goldenrod}{ ▏ }}}$ 0.5%, 7.55 KB
dist/config/sanitize.js	${{\color{Goldenrod}{ ▏ }}}$ 0.5%, 6.98 KB
dist/collections/endpoints	${{\color{Goldenrod}{ }}}$ 0.4%, 6.12 KB
dist/queues/config	${{\color{Goldenrod}{ }}}$ 0.4%, 5.59 KB
dist/uploads/endpoints	${{\color{Goldenrod}{ }}}$ 0.4%, 5.56 KB
(other)	${{\color{Goldenrod}{ ███████▊ }}}$ 31.2%, 437.61 KB

Meta file: packages/payload/meta_shared.json, Out file: esbuild/exports/shared.js

Path	Size
../../node_modules	${{\color{Goldenrod}{ █████████████████▉ }}}$ 71.9%, 150.13 KB
dist/fields/validations.js	${{\color{Goldenrod}{ █▎ }}}$ 5.1%, 10.73 KB
dist/fields/config	${{\color{Goldenrod}{ ▋ }}}$ 2.8%, 5.82 KB
dist/utilities/traverseFields.js	${{\color{Goldenrod}{ ▌ }}}$ 2.1%, 4.44 KB
dist/collections/config	${{\color{Goldenrod}{ ▍ }}}$ 1.6%, 3.32 KB
dist/config/orderable	${{\color{Goldenrod}{ ▍ }}}$ 1.5%, 3.13 KB
dist/fields/baseFields	${{\color{Goldenrod}{ ▎ }}}$ 1.3%, 2.79 KB
dist/utilities/deepCopyObject.js	${{\color{Goldenrod}{ ▎ }}}$ 1.3%, 2.69 KB
dist/config/client.js	${{\color{Goldenrod}{ ▎ }}}$ 1.3%, 2.68 KB
dist/auth/cookies.js	${{\color{Goldenrod}{ ▏ }}}$ 0.7%, 1.55 KB
dist/utilities/flattenTopLevelFields.js	${{\color{Goldenrod}{ ▏ }}}$ 0.7%, 1.41 KB
dist/utilities/getVersionsConfig.js	${{\color{Goldenrod}{ ▏ }}}$ 0.5%, 1.04 KB
dist/globals/config	${{\color{Goldenrod}{ }}}$ 0.4%, 939 B
dist/utilities/flattenAllFields.js	${{\color{Goldenrod}{ }}}$ 0.4%, 793 B
dist/utilities/unflatten.js	${{\color{Goldenrod}{ }}}$ 0.4%, 779 B
dist/utilities/sanitizeUserDataForEmail.js	${{\color{Goldenrod}{ }}}$ 0.3%, 713 B
dist/auth/extractJWT.js	${{\color{Goldenrod}{ }}}$ 0.3%, 696 B
dist/utilities/getFieldPermissions.js	${{\color{Goldenrod}{ }}}$ 0.3%, 651 B
dist/errors/ValidationError.js	${{\color{Goldenrod}{ }}}$ 0.3%, 577 B
dist/bin/generateImportMap	${{\color{Goldenrod}{ }}}$ 0.3%, 561 B
(other)	${{\color{Goldenrod}{ ███████ }}}$ 28.1%, 58.59 KB

Meta file: packages/richtext-lexical/meta_client.json, Out file: esbuild/exports/client_optimized/index.js

Path	Size
dist/features/blocks	${{\color{Goldenrod}{ ███▎ }}}$ 13.2%, 37.20 KB
dist/lexical/ui	${{\color{Goldenrod}{ ███ }}}$ 12.1%, 34.16 KB
dist/lexical/plugins	${{\color{Goldenrod}{ ██▉ }}}$ 11.8%, 33.18 KB
dist/features/experimental_table	${{\color{Goldenrod}{ ██▍ }}}$ 9.6%, 27.22 KB
dist/features/link	${{\color{Goldenrod}{ █▋ }}}$ 6.7%, 18.82 KB
dist/features/toolbars	${{\color{Goldenrod}{ █▍ }}}$ 5.9%, 16.58 KB
dist/features/upload	${{\color{Goldenrod}{ █▎ }}}$ 5.0%, 14.09 KB
dist/features/textState	${{\color{Goldenrod}{ ▉ }}}$ 3.9%, 11.08 KB
dist/lexical/utils	${{\color{Goldenrod}{ ▉ }}}$ 3.5%, 10.02 KB
dist/features/relationship	${{\color{Goldenrod}{ ▊ }}}$ 3.4%, 9.61 KB
dist/features/converters	${{\color{Goldenrod}{ ▊ }}}$ 3.0%, 8.36 KB
dist/utilities/fieldsDrawer	${{\color{Goldenrod}{ ▋ }}}$ 2.9%, 8.12 KB
dist/features/debug	${{\color{Goldenrod}{ ▋ }}}$ 2.6%, 7.40 KB
dist/lexical/config	${{\color{Goldenrod}{ ▍ }}}$ 1.8%, 5.14 KB
dist/features/lists	${{\color{Goldenrod}{ ▎ }}}$ 1.3%, 3.64 KB
dist/features/format	${{\color{Goldenrod}{ ▎ }}}$ 1.2%, 3.28 KB
dist/lexical/LexicalEditor.js	${{\color{Goldenrod}{ ▎ }}}$ 1.1%, 3.23 KB
dist/features/horizontalRule	${{\color{Goldenrod}{ ▎ }}}$ 1.1%, 3.18 KB
dist/field/Field.js	${{\color{Goldenrod}{ ▎ }}}$ 1.0%, 2.88 KB
dist/lexical/nodes	${{\color{Goldenrod}{ ▏ }}}$ 0.9%, 2.66 KB
(other)	${{\color{Goldenrod}{ █████████████████████▋ }}}$ 86.8%, 245.15 KB

Meta file: packages/ui/meta_client.json, Out file: esbuild/exports/client_optimized/index.js

Path	Size
dist/exports/client	${{\color{Goldenrod}{ █████████████████████████ }}}$ 100.0%, 26.63 KB

Meta file: packages/ui/meta_shared.json, Out file: esbuild/exports/shared_optimized/index.js

Path	Size
dist/graphics/Logo	${{\color{Goldenrod}{ ███████▋ }}}$ 30.5%, 5.57 KB
../../node_modules	${{\color{Goldenrod}{ ███▌ }}}$ 14.5%, 2.65 KB
dist/graphics/Icon	${{\color{Goldenrod}{ ██ }}}$ 8.3%, 1.51 KB
dist/utilities/formatDocTitle	${{\color{Goldenrod}{ █▊ }}}$ 7.2%, 1.32 KB
dist/providers/TableColumns	${{\color{Goldenrod}{ █▏ }}}$ 4.7%, 866 B
dist/utilities/getGlobalData.js	${{\color{Goldenrod}{ █ }}}$ 4.2%, 762 B
dist/utilities/api.js	${{\color{Goldenrod}{ █ }}}$ 4.1%, 756 B
dist/utilities/groupNavItems.js	${{\color{Goldenrod}{ █ }}}$ 4.1%, 745 B
dist/elements/Translation	${{\color{Goldenrod}{ ▋ }}}$ 2.7%, 493 B
dist/utilities/handleTakeOver.js	${{\color{Goldenrod}{ ▌ }}}$ 2.4%, 440 B
dist/utilities/traverseForLocalizedFields.js	${{\color{Goldenrod}{ ▌ }}}$ 2.3%, 419 B
dist/elements/withMergedProps	${{\color{Goldenrod}{ ▍ }}}$ 1.9%, 339 B
dist/utilities/getNavGroups.js	${{\color{Goldenrod}{ ▍ }}}$ 1.9%, 338 B
dist/utilities/getVisibleEntities.js	${{\color{Goldenrod}{ ▍ }}}$ 1.8%, 329 B
dist/elements/WithServerSideProps	${{\color{Goldenrod}{ ▎ }}}$ 1.3%, 232 B
dist/layouts/Root	${{\color{Goldenrod}{ ▎ }}}$ 1.3%, 230 B
dist/utilities/handleGoBack.js	${{\color{Goldenrod}{ ▎ }}}$ 1.0%, 180 B
dist/fields/mergeFieldStyles.js	${{\color{Goldenrod}{ ▏ }}}$ 0.9%, 158 B
dist/forms/Form	${{\color{Goldenrod}{ ▏ }}}$ 0.8%, 152 B
dist/utilities/handleBackToDashboard.js	${{\color{Goldenrod}{ ▏ }}}$ 0.8%, 152 B
(other)	${{\color{Goldenrod}{ █████████████████▍ }}}$ 69.5%, 12.68 KB

Details

Next to the size is how much the size has increased or decreased compared with the base branch of this PR.

• ‼️: Size increased by 20% or more. Special attention should be given to this.
• ⚠️: Size increased in acceptable range (lower than 20%).
• ✅: No change or even downsized.
• 🗑️: The out file is deleted: not found in base branch.
• 🆕: The out file is newly found: will be added to base branch.