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 8 Oct 2026 13:07 UTC.
Upstream edited
Recorded here
Lines+30added
Lines−6removed
From line
12
where the diff opens
First seen
14 Aug 2026
this site's first read of the page
Recorded edits3to this page, all time
The whole hunk
from line 12, old and new numbered
/
from line 12
1212
1313All 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).
1414
15<Frame caption="The MCP Inspector web client, connected to a server, with the monitoring sidebar pinned so protocol traffic stays visible while you work.">
16 <img src="https://mintcdn.com/mcp/gk28X8wi_tbRYzej/images/inspector/web-monitor-sidebar.png?fit=max&auto=format&n=gk28X8wi_tbRYzej&q=85&s=eef6e546b9831b3d169e26bba8c54ce3" width="3840" height="2160" data-path="images/inspector/web-monitor-sidebar.png" />
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.
16
17<Frame caption="The 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.">
18 <img src="https://mintcdn.com/mcp/pUebPdrb6PY5_mfH/images/inspector/web-monitor-sidebar.png?fit=max&auto=format&n=pUebPdrb6PY5_mfH&q=85&s=2ced9eeefa020be53fe4fe957b7d07c6" width="3840" height="2160" data-path="images/inspector/web-monitor-sidebar.png" />
1719</Frame>
1820
1921## Quickstart
from line 32
3032 npx @modelcontextprotocol/inspector
3133 ```
3234
33 The command prints a URL containing a one-time session token; open it in your browser. See [Web client](/docs/2026-07-28/tools/inspector/web).
35 The 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).
3436 </Tab>
3537
3638 <Tab title="CLI">
from line 83
8183
8284Always read a server's own README first, since every server requires different commands and arguments.
8385
86<Warning>
87 **The Inspector stores secrets (OAuth tokens, OAuth client secrets, and stdio
88 `env:` values) in the OS keychain when one is available.** On a machine with
89 no keychain (Linux without libsecret or a Secret Service, headless and SSH
90 sessions, Termux, and containers with a mounted volume) they are saved to
91 `~/.mcp-inspector/secrets.json` instead, **unencrypted unless you supply a
92 key**. See [Where secrets are
93 stored](/docs/2026-07-28/tools/inspector/configuration#where-secrets-are-stored)
94 for how to get a keychain back, encrypt the file, or keep secrets in memory
95 only.
96</Warning>
97
8498## Launcher flags vs. client flags
8599
86100`mcp-inspector`, the binary that `npx @modelcontextprotocol/inspector` runs, is a thin launcher. It owns only two things:
from line 113
99113</Note>
100114
101115<Note>
102 `--help` behaves differently with and without a mode flag. Bare `mcp-inspector --help` prints the launcher's help and exits. With a mode flag it is
103 forwarded, so `mcp-inspector --cli --help` prints the CLI's full flag
104 reference instead.
116 `--help` behaves differently with and without a mode flag. Without one,
117 `-h`/`--help` anywhere on the command line (even after a server command)
118 prints the launcher's help and exits. With a mode flag it is forwarded, so
119 `mcp-inspector --cli --help` prints the CLI's full flag reference instead.
105120</Note>
106121
107122## Where to go next
from line 147
132147 <Card title="Protocol eras" icon="code-branch" href="/docs/2026-07-28/tools/inspector/protocol-eras">
133148 Legacy vs. modern (2026-07-28) operation, and how every tab changes between
134149 protocol eras.
150 </Card>
151
152 <Card title="mcpdo connection client" icon="plug" href="/docs/2026-07-28/tools/inspector/mcpdo">
153 Connect once, then run many commands against a named connection.
154 </Card>
155
156 <Card title="Security" icon="shield-halved" href="/docs/2026-07-28/tools/inspector/security">
157 The threat model: the web backend's token, Docker, secret storage, stdio
158 servers, and the mcpdo daemon.
135159 </Card>
136160
137161 <Card title="Recipes" icon="book" href="/docs/2026-07-28/tools/inspector/recipes">
No line in this hunk matches that.