mcphost

host.tool_share

Share one of this tenant's published tools with everyone (visibility: "public") or with a named group this tenant owns (visibility: "group", group: ). The tool keeps running in this tenant's own sandbox with this tenant's own secrets; a caller reaches it as <this tenant's namespace>..

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "name": "<name>",
      "visibility": "<visibility>"
    },
    "name": "host.tool_share"
  }
}

Input Schema

Name	Required	Description
`name`	Yes	Local name of the tool to share.
`tags`	No	Catalog tags merged into the tool's existing ones (same rules as host.tool_publish).
`group`	No	Required when visibility is "group"; must already exist (host.group.create).
`scopes`	No	What the grantee may do: call, read_source, fork. Default ["call"] (["call","read_source"] with expose_spec: true). url shares allow only call.
`tenant_key`	No	The key `signup` returned. Optional on the connection that ran signup (or host.redeem): that connection is already bound to the tenant it created, so later calls on it need no tenant_key. On a connection with no Authorization: Bearer header and no prior signup, omitting it implicitly signs that connection up as a brand-new tenant and runs this call as it -- see host.whoami's source field. When both a header and this argument are present, the header wins.
`visibility`	Yes	"public" (needs a passing dry run of the current version), "unlisted", "group" or "url".
`description`	No	Catalog-facing blurb; shown by host.catalog.search/get.
`expose_spec`	No	Default false. When true, any tenant this tool is shared with may call host.tool_spec_shared to read its (redacted) spec.
`rate_per_hour_per_caller`	No	Optional cap (1..10000) on calls per hour from any one grantee.

Output Schema

Name	Required	Description	Default
`url`	No
`name`	Yes
`next`	No
`group`	Yes
`visibility`	Yes
`description`	Yes
`expose_spec`	Yes
`welcome_back`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed3 schema fields changedOct 24, 2026
- addedInput schema / properties / rate_per_hour_per_caller / maximum
```
Added value: +10000
```
- addedInput schema / properties / rate_per_hour_per_caller / minimum
```
Added value: +1
```
- addedInput schema / properties / scopes / minItems
```
Added value: +1
```

Changed2 schema fields changedOct 18, 2026

addedInput schema / properties / rate_per_hour_per_caller

Added value: +{
+  "description": "Optional cap (1..10000) on calls per hour from any one grantee.",
+  "type": "integer"
+}

addedInput schema / properties / scopes

Added value: +{
+  "description": "What the grantee may do: call, read_source, fork. Default [\"call\"] ([\"call\",\"read_source\"] with expose_spec: true). url shares allow only call.",
+  "items": {
+    "enum": [
+      "call",
+      "read_source",
+      "fork"
+    ],
+    "type": "string"
+  },
+  "type": "array"
+}

Changed2 schema fields changedOct 18, 2026

addedOutput schema / $defs

Added value: +{
+  "ErrorEnvelope": {
+    "properties": {
+      "code": {
+        "type": "integer"
+      },
+      "data": {
+        "properties": {
+          "error_code": {
+            "type": "string"
+          },
+          "retryable": {
+            "type": "boolean"
+          }
+        },
+        "required": [
+          "error_code"
+        ],
+        "type": "object"
+      },
+      "message": {
+        "type": "string"
+      }
+    },
+    "required": [
+      "code",
+      "message",
+      "data"
+    ],
+    "type": "object"
+  }
+}

addedOutput schema / x-error-envelope

Added value: +{
+  "$ref": "#/$defs/ErrorEnvelope"
+}

Changed1 schema field changedOct 18, 2026
- addedInput schema / x-mcphost-validated
```
Added value: +true
```

Changed3 schema fields changedOct 17, 2026

addedInput schema / properties / tags

Added value: +{
+  "description": "Catalog tags merged into the tool's existing ones (same rules as host.tool_publish).",
+  "items": {
+    "type": "string"
+  },
+  "type": "array"
+}

changedInput schema / properties / visibility / description

Previous value: -"\"public\" or \"group\"."New value: +"\"public\" (needs a passing dry run of the current version), \"unlisted\", \"group\" or \"url\"."

addedInput schema / properties / visibility / enum

Added value: +[
+  "unlisted",
+  "group",
+  "public",
+  "url"
+]

Changed13 schema fields changedOct 16, 2026
- changedOutput schema / properties / next / properties / tool / type
```
Previous value: -"string"New value: +[
+  "string",
+  "null"
+]
```
- changedOutput schema / properties / next / properties / why / type
```
Previous value: -"string"New value: +[
+  "string",
+  "null"
+]
```
- changedOutput schema / properties / next / type
```
Previous value: -"object"New value: +[
+  "object",
+  "null"
+]
```
- changedOutput schema / properties / url / type
```
Previous value: -"string"New value: +[
+  "string",
+  "null"
+]
```
- removedOutput schema / properties / welcome_back / properties / last_note / type
```
Removed value: -"null"
```
- changedOutput schema / properties / welcome_back / properties / last_seen / type
```
Previous value: -"string"New value: +[
+  "string",
+  "null"
+]
```
- changedOutput schema / properties / welcome_back / properties / notes / type
```
Previous value: -"integer"New value: +[
+  "integer",
+  "null"
+]
```
- changedOutput schema / properties / welcome_back / properties / since_you_left / properties / calls / type
```
Previous value: -"integer"New value: +[
+  "integer",
+  "null"
+]
```
- changedOutput schema / properties / welcome_back / properties / since_you_left / properties / days / type
```
Previous value: -"integer"New value: +[
+  "integer",
+  "null"
+]
```
- changedOutput schema / properties / welcome_back / properties / since_you_left / properties / inbox / type
```
Previous value: -"integer"New value: +[
+  "integer",
+  "null"
+]
```
- changedOutput schema / properties / welcome_back / properties / since_you_left / properties / runs / type
```
Previous value: -"integer"New value: +[
+  "integer",
+  "null"
+]
```
- changedOutput schema / properties / welcome_back / properties / since_you_left / type
```
Previous value: -"object"New value: +[
+  "object",
+  "null"
+]
```
- changedOutput schema / properties / welcome_back / type
```
Previous value: -"object"New value: +[
+  "object",
+  "null"
+]
```

Changed1 schema field changedOct 12, 2026

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "properties": {
+    "description": {
+      "type": [
+        "string",
+        "null"
+      ]
+    },
+    "expose_spec": {
+      "type": "boolean"
+    },
+    "group": {
+      "type": [
+        "string",
+        "null"
+      ]
+    },
+    "name": {
+      "type": "string"
+    },
+    "next": {
+      "properties": {
+        "tool": {
+          "type": "string"
+        },
+        "why": {
+          "type": "string"
+        }
+      },
+      "type": "object"
+    },
+    "url": {
+      "type": "string"
+    },
+    "visibility": {
+      "type": "string"
+    },
+    "welcome_back": {
+      "properties": {
+        "last_note": {
+          "type": "null"
+        },
+        "last_seen": {
+          "type": "string"
+        },
+        "notes": {
+          "type": "integer"
+        },
+        "since_you_left": {
+          "properties": {
+            "calls": {
+              "type": "integer"
+            },
+            "days": {
+              "type": "integer"
+            },
+            "inbox": {
+              "type": "integer"
+            },
+            "runs": {
+              "type": "integer"
+            }
+          },
+          "type": "object"
+        }
+      },
+      "type": "object"
+    }
+  },
+  "required": [
+    "description",
+    "expose_spec",
+    "group",
+    "name",
+    "visibility"
+  ],
+  "type": "object"
+}

Changed1 schema field changedOct 4, 2026

changedInput schema / properties / tenant_key / description

Previous value: -"The key `signup` returned. Optional on the connection that ran signup (or host.redeem): that connection is already bound to the tenant it created, so later calls on it need no tenant_key. Required only when this connection carries no Authorization: Bearer header and never ran signup -- when both a header and this argument are present, the header wins. Omitting it on such a connection returns tenant_key_missing (-32602)."New value: +"The key `signup` returned. Optional on the connection that ran signup (or host.redeem): that connection is already bound to the tenant it created, so later calls on it need no tenant_key. On a connection with no Authorization: Bearer header and no prior signup, omitting it implicitly signs that connection up as a brand-new tenant and runs this call as it -- see host.whoami's source field. When both a header and this argument are present, the header wins."

Changed1 schema field changedOct 4, 2026

addedInput schema / x-deprecated

Added value: +{
+  "replaced_by": "host.tool.share",
+  "sunset": "2026-12-31"
+}

Changed1 schema field changedOct 3, 2026
- addedInput schema / additionalProperties
```
Added value: +false
```

Changed1 schema field changedSep 30, 2026

changedInput schema / properties / tenant_key / description

Previous value: -"The key `signup` returned. Required only when this connection carries no Authorization: Bearer header -- when both are present, the header wins. Omitting it on a connection with no header returns tenant_key_missing (-32602)."New value: +"The key `signup` returned. Optional on the connection that ran signup (or host.redeem): that connection is already bound to the tenant it created, so later calls on it need no tenant_key. Required only when this connection carries no Authorization: Bearer header and never ran signup -- when both a header and this argument are present, the header wins. Omitting it on such a connection returns tenant_key_missing (-32602)."

Changed1 schema field changedSep 30, 2026

changedInput schema / properties / tenant_key / description

Previous value: -"The key `signup` returned. Required only when this connection carries no Authorization: Bearer header -- when both are present, the header wins."New value: +"The key `signup` returned. Required only when this connection carries no Authorization: Bearer header -- when both are present, the header wins. Omitting it on a connection with no header returns tenant_key_missing (-32602)."

Changed1 schema field changedSep 28, 2026

addedInput schema / properties / expose_spec

Added value: +{
+  "description": "Default false. When true, any tenant this tool is shared with may call host.tool_spec_shared to read its (redacted) spec.",
+  "type": "boolean"
+}

AddedSep 11, 2026

TDQS

A3.5/5.0

Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are supplied, so the description carries the full burden; it does disclose the key behavioral fact that the tool keeps running in this tenant's sandbox with this tenant's own secrets and is reached as <namespace>.<name>. That is genuinely useful context, but it omits auth/permission requirements, whether the share is idempotent or revocable, what happens to existing grants, and the rate-limiting/scope behavior that governs what a grantee can actually do.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, zero filler, with the recipient modes front-loaded and the hosting/namespace model following as necessary context. Every clause carries information an agent cannot get from the name alone.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists, so return values need not be explained, but for a 9-parameter mutation tool with no annotations the description is thin: it never covers the unlisted/url visibilities, the scopes grant model, per-caller rate caps, or the fact that the definition is deprecated in favor of host.tool.share (2026-12-31). Adequate for the core share semantics, not complete.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the baseline is 3; every parameter (tags, group, scopes, expose_spec, rate_per_hour_per_caller, tenant_key) is already documented in the schema. The description adds meaning only for visibility/group, leaving scopes and the exposure controls entirely to the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb (share) and resource (one of this tenant's published tools) plus the two recipient modes, so the agent knows exactly what the call does. It implicitly depends on host.tool_publish having run first but never names that sibling or contrasts sharing with publishing/forking, so sibling differentiation is only partial.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives the conditional for two modes: 'everyone (visibility: public)' vs 'a named group this tenant owns (visibility: group, group: <name>)', which is real routing guidance. However, it ignores the other two enum values the schema allows (unlisted, url) and offers no exclusions, prerequisites (public needs a passing dry run), or alternatives such as host.tool_publish or host.tool_call.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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host.tool_share

Tool call template

Input Schema

Output Schema

Schema Changelog

TDQS

Glama MCP Gateway

Resources