MCP Inspector changeddocs/2026-07-28/tools/inspector
Nearest release: v2.1.295, published 5 hours after upstream edited the page. Shown because the two are within 24 hours of each other. Nothing here says the release caused the edit.
Upstream edited this page at 8 Oct 2026 12:58 UTC, give or take a minute or two: the time comes from Anthropic’s own sitemap rather than from a commit. This site recorded the change at 22 Oct 2026 20:37 UTC.
Upstream edited
Recorded here
Lines+20added
Lines−18removed
From line
2
where the diff opens
First seen
14 Aug 2026
this site's first read of the page
Recorded edits5to this page, all time
The whole hunk
from line 2, old and new numbered
/
from line 2
22
33> Interactive developer tooling for testing and debugging MCP servers, in the browser, on the command line, and in the terminal
44
5The [MCP Inspector](https://github.com/modelcontextprotocol/inspector) is the reference developer tool for testing and debugging [MCP servers](/docs/2026-07-28/learn/server-concepts). It ships as a single package, `@modelcontextprotocol/inspector`, providing **three clients behind one binary**:
5The [MCP Inspector](https://github.com/modelcontextprotocol/inspector) is the reference developer tool for testing and debugging [MCP servers](/docs/2026-07-28/learn/server-concepts.md). It ships as a single package, `@modelcontextprotocol/inspector`, providing **three clients behind one binary**:
66
77| Client | Invocation | What it's for |
88| - | - | - |
from line 10
1010| **CLI** | `npx @modelcontextprotocol/inspector --cli` | A scriptable, machine-readable client for CI, shell pipelines, and coding agents. |
1111| **TUI** | `npx @modelcontextprotocol/inspector --tui` | An interactive terminal UI, for when a browser isn't available or wanted. |
1212
13All three are built on the same shared core, so a connection behaves identically across them: the same transports, the same configuration files, the same OAuth state on disk, and the same [protocol-era](/docs/2026-07-28/tools/inspector/protocol-eras) negotiation (legacy vs. modern 2026-07-28).
13All three are built on the same shared core, so a connection behaves identically across them: the same transports, the same configuration files, the same OAuth state on disk, and the same [protocol-era](/docs/2026-07-28/tools/inspector/protocol-eras.md) negotiation (legacy vs. modern 2026-07-28).
1414
15The package also installs **`mcpdo`**, an experimental [connection client](/docs/2026-07-28/tools/inspector/mcpdo) that connects to a server once and keeps it open across many commands, on the same core.
15The package also installs **`mcpdo`**, an experimental [connection client](/docs/2026-07-28/tools/inspector/mcpdo.md) that connects to a server once and keeps it open across many commands, on the same core.
1616
1717
1818
19The MCP Inspector web client after a tool call, with the monitoring sidebar pinned and widened so the JSON-RPC exchange stays readable while you work.
20
1921## Quickstart
2022
2123The Inspector requires **Node 22.19.0 or newer** and runs directly through `npx`. No installation is required:
from line 32
3032npx @modelcontextprotocol/inspector
3133```
3234
33The command prints a URL carrying a per-launch API token and opens it in your browser (set `MCP_AUTO_OPEN_ENABLED=false` to stop it opening). See [Web client](/docs/2026-07-28/tools/inspector/web).
35The command prints a URL carrying a per-launch API token and opens it in your browser (set `MCP_AUTO_OPEN_ENABLED=false` to stop it opening). See [Web client](/docs/2026-07-28/tools/inspector/web.md).
3436
3537**CLI**
3638
from line 45
4345 --method tools/call --tool-name get_weather --tool-arg city=Boston --format json | jq .result
4446```
4547
46See [CLI client](/docs/2026-07-28/tools/inspector/cli).
48See [CLI client](/docs/2026-07-28/tools/inspector/cli.md).
4749
4850**TUI**
4951
from line 53
5153npx @modelcontextprotocol/inspector --tui node path/to/server/index.js
5254```
5355
54See [TUI client](/docs/2026-07-28/tools/inspector/tui).
56See [TUI client](/docs/2026-07-28/tools/inspector/tui.md).
5557
5658### Inspecting published servers
5759
from line 87
8587> sessions, Termux, and containers with a mounted volume) they are saved to
8688> `~/.mcp-inspector/secrets.json` instead, **unencrypted unless you supply a
8789> key**. See [Where secrets are
88> stored](/docs/2026-07-28/tools/inspector/configuration#where-secrets-are-stored)
90> stored](/docs/2026-07-28/tools/inspector/configuration.md#where-secrets-are-stored)
8991> for how to get a keychain back, encrypt the file, or keep secrets in memory
9092> only.
9193
from line 98
96981. **The mode flag:** `--web` (default), `--cli`, or `--tui`. At most one; passing two errors with `Specify at most one of --web, --cli, or --tui.`
97992. **`-h` / `--help`.**
98100
99Everything else (`--catalog`, `--config`, `--server-url`, `--transport`, `--method`, the OAuth flags) is defined by the *client*, not the launcher, and the clients do not all define the same set. The [Configuration and flags](/docs/2026-07-28/tools/inspector/configuration) page is organized that way, by owner.
101Everything else (`--catalog`, `--config`, `--server-url`, `--transport`, `--method`, the OAuth flags) is defined by the *client*, not the launcher, and the clients do not all define the same set. The [Configuration and flags](/docs/2026-07-28/tools/inspector/configuration.md) page is organized that way, by owner.
100102
101103> [!NOTE]
102104>
from line 117
115117
116118## Where to go next
117119
118> **[Web client](/docs/2026-07-28/tools/inspector/web)**
120> **[Web client](/docs/2026-07-28/tools/inspector/web.md)**
119121>
120122> A tab-by-tab walkthrough of the graphical inspector.
121123
122> **[CLI client](/docs/2026-07-28/tools/inspector/cli)**
124> **[CLI client](/docs/2026-07-28/tools/inspector/cli.md)**
123125>
124126> Method reference, output formats, exit codes, and CI recipes.
125127
126> **[TUI client](/docs/2026-07-28/tools/inspector/tui)**
128> **[TUI client](/docs/2026-07-28/tools/inspector/tui.md)**
127129>
128130> Terminal navigation and keyboard reference.
129131
130> **[Configuration and flags](/docs/2026-07-28/tools/inspector/configuration)**
132> **[Configuration and flags](/docs/2026-07-28/tools/inspector/configuration.md)**
131133>
132134> Catalog vs. config files, the full per-client flag reference, and
133135> environment variables.
134136
135> **[Authorization](/docs/2026-07-28/tools/inspector/authorization)**
137> **[Authorization](/docs/2026-07-28/tools/inspector/authorization.md)**
136138>
137139> The OAuth flow end to end, mid-session re-authorization, and loopback
138140> callbacks.
139141
140> **[Protocol eras](/docs/2026-07-28/tools/inspector/protocol-eras)**
142> **[Protocol eras](/docs/2026-07-28/tools/inspector/protocol-eras.md)**
141143>
142144> Legacy vs. modern (2026-07-28) operation, and how every tab changes between
143145> protocol eras.
144146
145> **[mcpdo connection client](/docs/2026-07-28/tools/inspector/mcpdo)**
147> **[mcpdo connection client](/docs/2026-07-28/tools/inspector/mcpdo.md)**
146148>
147149> Connect once, then run many commands against a named connection.
148150
149> **[Security](/docs/2026-07-28/tools/inspector/security)**
151> **[Security](/docs/2026-07-28/tools/inspector/security.md)**
150152>
151153> The threat model: the web backend's token, Docker, secret storage, stdio
152154> servers, and the mcpdo daemon.
153155
154> **[Recipes](/docs/2026-07-28/tools/inspector/recipes)**
156> **[Recipes](/docs/2026-07-28/tools/inspector/recipes.md)**
155157>
156158> Importing client configs, reviewing MCP Apps, Docker, and network hosting.
157159
158> **[Debugging guide](/docs/2026-07-28/tools/debugging)**
160> **[Debugging guide](/docs/2026-07-28/tools/debugging.md)**
159161>
160162> Broader debugging strategies beyond the Inspector.
161163
No line in this hunk matches that.