Polarion MCP Server

getProjectCustomFields

Read-only

Retrieve defined custom fields for a resource type and target type within a specific Polarion project by providing project, resource, and target IDs.

Instructions

Returns the defined Custom Fields for the resource type and target type in the Project context. Scope: one project (requires a project ID). To act across all projects, use getGlobalCustomFields instead.

Input Schema

Name	Required	Description	Default
`fields`	No	Sparse fieldset selector: an object keyed by resource type (e.g. `workitems`) whose value is a comma-separated list of attribute names to return (e.g. `id,title,status`), reducing payload size. Omit to return the default field set.
`include`	No	Comma-separated list of related resource types to embed in the response (e.g. `author,attachments`) so they don't require a separate follow-up call. Omit to return only the primary resource.
`projectId`	Yes	The Polarion project ID (its URL segment, e.g. `myproject`), case-sensitive. Required to scope the request to one project. If the ID is unknown, ask the user; getProjects lists IDs only with global read access.
`targetType`	Yes	The configured subtype for this enumeration or custom field (e.g. `requirement` for a Work Item type). Use `~` (without quotes) when the configuration applies to every subtype.
`resourceType`	Yes	The Resource Type.
`response_format`	No	Response detail level. concise removes redundant HTML and JSON:API metadata and may use a small default fieldset on large lists; detailed preserves the complete response. Defaults to detailed.	detailed

Output Schema

Name	Required	Description
`data`	No
`links`	No
`included`	No	Related entities might be returned, see <a href="https://docs.sw.siemens.com/en-US/doc/230235217/PL20250606201928474.polarion_help_sc.xid2134849/xid2134871" target="_blank">REST API User Guide</a>.

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedv1.4.4Oct 29, 2026

changedInput schema / properties / projectId / description

Previous value: -"The Polarion project ID (its URL segment, e.g. `myproject`), case-sensitive. Required to scope the request to one project; call getProjects to list valid IDs."New value: +"The Polarion project ID (its URL segment, e.g. `myproject`), case-sensitive. Required to scope the request to one project. If the ID is unknown, ask the user; getProjects lists IDs only with global read access."

Changed2 schema fields changedv1.4.0Oct 24, 2026

addedInput schema / properties / response_format

Added value: +{
+  "default": "detailed",
+  "description": "Response detail level. concise removes redundant HTML and JSON:API metadata and may use a small default fieldset on large lists; detailed preserves the complete response. Defaults to detailed.",
+  "enum": [
+    "concise",
+    "detailed"
+  ],
+  "type": "string"
+}

changedInput schema / properties / targetType / description

Previous value: -"Identifies the target resource type this operation applies to (e.g. `workitem`). Use `~` (no quotes) to mean no specific target type."New value: +"The configured subtype for this enumeration or custom field (e.g. `requirement` for a Work Item type). Use `~` (without quotes) when the configuration applies to every subtype."

Changed56 schema fields changedv1.3.1Oct 22, 2026
- changedOutput schema / properties / data / properties / attributes / properties / fields / items / properties / defaultValue / type
```
Previous value: -"string"New value: +[
+  "string",
+  "number",
+  "integer",
+  "boolean",
+  "null"
+]
```
- changedOutput schema / properties / data / properties / attributes / properties / fields / items / properties / dependsOn / type
```
Previous value: -"string"New value: +[
+  "string",
+  "number",
+  "integer",
+  "boolean",
+  "null"
+]
```
- changedOutput schema / properties / data / properties / attributes / properties / fields / items / properties / description / type
```
Previous value: -"string"New value: +[
+  "string",
+  "number",
+  "integer",
+  "boolean",
+  "null"
+]
```
- changedOutput schema / properties / data / properties / attributes / properties / fields / items / properties / id / type
```
Previous value: -"string"New value: +[
+  "string",
+  "number",
+  "integer",
+  "boolean",
+  "null"
+]
```
- changedOutput schema / properties / data / properties / attributes / properties / fields / items / properties / name / type
```
Previous value: -"string"New value: +[
+  "string",
+  "number",
+  "integer",
+  "boolean",
+  "null"
+]
```
- removedOutput schema / properties / data / properties / attributes / properties / fields / items / properties / parameters / items / properties / key / example
```
Removed value: -"parameter1"
```
- changedOutput schema / properties / data / properties / attributes / properties / fields / items / properties / parameters / items / properties / key / type
```
Previous value: -"string"New value: +[
+  "string",
+  "number",
+  "integer",
+  "boolean",
+  "null"
+]
```
- removedOutput schema / properties / data / properties / attributes / properties / fields / items / properties / parameters / items / properties / name / example
```
Removed value: -"parameter1"
```
- changedOutput schema / properties / data / properties / attributes / properties / fields / items / properties / parameters / items / properties / name / type
```
Previous value: -"string"New value: +[
+  "string",
+  "number",
+  "integer",
+  "boolean",
+  "null"
+]
```
- removedOutput schema / properties / data / properties / attributes / properties / fields / items / properties / parameters / items / properties / title / example
```
Removed value: -"MyParameter"
```
- changedOutput schema / properties / data / properties / attributes / properties / fields / items / properties / parameters / items / properties / title / type
```
Previous value: -"string"New value: +[
+  "string",
+  "number",
+  "integer",
+  "boolean",
+  "null"
+]
```
- changedOutput schema / properties / data / properties / attributes / properties / fields / items / properties / parameters / items / type
```
Previous value: -"object"New value: +[
+  "object",
+  "null"
+]
```
- changedOutput schema / properties / data / properties / attributes / properties / fields / items / properties / parameters / type
```
Previous value: -"array"New value: +[
+  "array",
+  "null"
+]
```
- changedOutput schema / properties / data / properties / attributes / properties / fields / items / properties / required / type
```
Previous value: -"boolean"New value: +[
+  "string",
+  "number",
+  "integer",
+  "boolean",
+  "null"
+]
```
- removedOutput schema / properties / data / properties / attributes / properties / fields / items / properties / type / properties / kind / example
```
Removed value: -"string"
```
- changedOutput schema / properties / data / properties / attributes / properties / fields / items / properties / type / properties / kind / type
```
Previous value: -"string"New value: +[
+  "string",
+  "number",
+  "integer",
+  "boolean",
+  "null"
+]
```
- changedOutput schema / properties / data / properties / attributes / properties / fields / items / properties / type / type
```
Previous value: -"object"New value: +[
+  "object",
+  "null"
+]
```
- changedOutput schema / properties / data / properties / attributes / properties / fields / items / type
```
Previous value: -"object"New value: +[
+  "object",
+  "null"
+]
```
- changedOutput schema / properties / data / properties / attributes / properties / fields / type
```
Previous value: -"array"New value: +[
+  "array",
+  "null"
+]
```
- removedOutput schema / properties / data / properties / attributes / properties / resourceType / example
```
Removed value: -"id"
```
- changedOutput schema / properties / data / properties / attributes / properties / resourceType / type
```
Previous value: -"string"New value: +[
+  "string",
+  "number",
+  "integer",
+  "boolean",
+  "null"
+]
```
- removedOutput schema / properties / data / properties / attributes / properties / targetType / example
```
Removed value: -"id"
```
- changedOutput schema / properties / data / properties / attributes / properties / targetType / type
```
Previous value: -"string"New value: +[
+  "string",
+  "number",
+  "integer",
+  "boolean",
+  "null"
+]
```
- changedOutput schema / properties / data / properties / attributes / type
```
Previous value: -"object"New value: +[
+  "object",
+  "null"
+]
```
- removedOutput schema / properties / data / properties / id / example
```
Removed value: -"MyProjectId/workitems/epic"
```
- changedOutput schema / properties / data / properties / id / type
```
Previous value: -"string"New value: +[
+  "string",
+  "number",
+  "integer",
+  "boolean",
+  "null"
+]
```
- removedOutput schema / properties / data / properties / links / properties / self / example
```
Removed value: -"server-host-name/application-path/projects/MyProjectId/customfields/workitems/epic"
```
- changedOutput schema / properties / data / properties / links / properties / self / type
```
Previous value: -"string"New value: +[
+  "string",
+  "number",
+  "integer",
+  "boolean",
+  "null"
+]
```
- changedOutput schema / properties / data / properties / links / type
```
Previous value: -"object"New value: +[
+  "object",
+  "null"
+]
```
- removedOutput schema / properties / data / properties / meta / properties / errors / items / properties / detail / example
```
Removed value: -"Unexpected token, BEGIN_ARRAY expected, but was : BEGIN_OBJECT (at $.data)"
```
- changedOutput schema / properties / data / properties / meta / properties / errors / items / properties / detail / type
```
Previous value: -"string"New value: +[
+  "string",
+  "number",
+  "integer",
+  "boolean",
+  "null"
+]
```
- removedOutput schema / properties / data / properties / meta / properties / errors / items / properties / source / properties / parameter / example
```
Removed value: -"revision"
```
- changedOutput schema / properties / data / properties / meta / properties / errors / items / properties / source / properties / parameter / type
```
Previous value: -"string"New value: +[
+  "string",
+  "number",
+  "integer",
+  "boolean",
+  "null"
+]
```
- removedOutput schema / properties / data / properties / meta / properties / errors / items / properties / source / properties / pointer / example
```
Removed value: -"$.data"
```
- changedOutput schema / properties / data / properties / meta / properties / errors / items / properties / source / properties / pointer / type
```
Previous value: -"string"New value: +[
+  "string",
+  "number",
+  "integer",
+  "boolean",
+  "null"
+]
```
- removedOutput schema / properties / data / properties / meta / properties / errors / items / properties / source / properties / resource / properties / id / example
```
Removed value: -"MyProjectId/id"
```
- changedOutput schema / properties / data / properties / meta / properties / errors / items / properties / source / properties / resource / properties / id / type
```
Previous value: -"string"New value: +[
+  "string",
+  "number",
+  "integer",
+  "boolean",
+  "null"
+]
```
- removedOutput schema / properties / data / properties / meta / properties / errors / items / properties / source / properties / resource / properties / type / example
```
Removed value: -"type"
```
- changedOutput schema / properties / data / properties / meta / properties / errors / items / properties / source / properties / resource / properties / type / type
```
Previous value: -"string"New value: +[
+  "string",
+  "number",
+  "integer",
+  "boolean",
+  "null"
+]
```
- changedOutput schema / properties / data / properties / meta / properties / errors / items / properties / source / properties / resource / type
```
Previous value: -"object"New value: +[
+  "object",
+  "null"
+]
```
- changedOutput schema / properties / data / properties / meta / properties / errors / items / properties / source / type
```
Previous value: -"object"New value: +[
+  "object",
+  "null"
+]
```
- removedOutput schema / properties / data / properties / meta / properties / errors / items / properties / status / example
```
Removed value: -"400"
```
- changedOutput schema / properties / data / properties / meta / properties / errors / items / properties / status / type
```
Previous value: -"string"New value: +[
+  "string",
+  "number",
+  "integer",
+  "boolean",
+  "null"
+]
```
- removedOutput schema / properties / data / properties / meta / properties / errors / items / properties / title / example
```
Removed value: -"Bad Request"
```
- changedOutput schema / properties / data / properties / meta / properties / errors / items / properties / title / type
```
Previous value: -"string"New value: +[
+  "string",
+  "number",
+  "integer",
+  "boolean",
+  "null"
+]
```
- changedOutput schema / properties / data / properties / meta / properties / errors / items / type
```
Previous value: -"object"New value: +[
+  "object",
+  "null"
+]
```
- changedOutput schema / properties / data / properties / meta / properties / errors / type
```
Previous value: -"array"New value: +[
+  "array",
+  "null"
+]
```
- changedOutput schema / properties / data / properties / meta / type
```
Previous value: -"object"New value: +[
+  "object",
+  "null"
+]
```
- removedOutput schema / properties / data / properties / type / enum
```
Removed value: -[
-  "customfields"
-]
```
- changedOutput schema / properties / data / properties / type / type
```
Previous value: -"string"New value: +[
+  "string",
+  "number",
+  "integer",
+  "boolean",
+  "null"
+]
```
- changedOutput schema / properties / data / type
```
Previous value: -"object"New value: +[
+  "object",
+  "null"
+]
```
- changedOutput schema / properties / included / items / type
```
Previous value: -"object"New value: +[
+  "object",
+  "null"
+]
```
- changedOutput schema / properties / included / type
```
Previous value: -"array"New value: +[
+  "array",
+  "null"
+]
```
- removedOutput schema / properties / links / properties / self / example
```
Removed value: -"server-host-name/application-path/projects/MyProjectId/customfields/workitems/epic"
```
- changedOutput schema / properties / links / properties / self / type
```
Previous value: -"string"New value: +[
+  "string",
+  "number",
+  "integer",
+  "boolean",
+  "null"
+]
```
- changedOutput schema / properties / links / type
```
Previous value: -"object"New value: +[
+  "object",
+  "null"
+]
```

Changed4 schema fields changedv1.2.0Sep 17, 2026

changedInput schema / properties / fields / description

Previous value: -"Filter returned resource fields. See <a href=\"https://docs.sw.siemens.com/en-US/doc/230235217/PL20250606201928474.polarion_help_sc.xid2134849/xid2134871\" target=\"_blank\">REST API User Guide</a> for details."New value: +"Sparse fieldset selector: an object keyed by resource type (e.g. `workitems`) whose value is a comma-separated list of attribute names to return (e.g. `id,title,status`), reducing payload size. Omit to return the default field set."

changedInput schema / properties / include / description

Previous value: -"Include related entities. See <a href=\"https://docs.sw.siemens.com/en-US/doc/230235217/PL20250606201928474.polarion_help_sc.xid2134849/xid2134871\" target=\"_blank\">REST API User Guide</a> for details."New value: +"Comma-separated list of related resource types to embed in the response (e.g. `author,attachments`) so they don't require a separate follow-up call. Omit to return only the primary resource."

changedInput schema / properties / projectId / description

Previous value: -"The Project ID."New value: +"The Polarion project ID (its URL segment, e.g. `myproject`), case-sensitive. Required to scope the request to one project; call getProjects to list valid IDs."

changedInput schema / properties / targetType / description

Previous value: -"The Type of the object. Use '~' without quotes to represent no target Type."New value: +"Identifies the target resource type this operation applies to (e.g. `workitem`). Use `~` (no quotes) to mean no specific target type."

Changed1 schema field changedv1.1.0Sep 11, 2026

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "properties": {
+    "data": {
+      "properties": {
+        "attributes": {
+          "properties": {
+            "fields": {
+              "items": {
+                "properties": {
+                  "defaultValue": {
+                    "type": "string"
+                  },
+                  "dependsOn": {
+                    "type": "string"
+                  },
+                  "description": {
+                    "type": "string"
+                  },
+                  "id": {
+                    "type": "string"
+                  },
+                  "name": {
+                    "type": "string"
+                  },
+                  "parameters": {
+                    "items": {
+                      "properties": {
+                        "key": {
+                          "example": "parameter1",
+                          "type": "string"
+                        },
+                        "name": {
+                          "example": "parameter1",
+                          "type": "string"
+                        },
+                        "title": {
+                          "example": "MyParameter",
+                          "type": "string"
+                        }
+                      },
+                      "type": "object"
+                    },
+                    "type": "array"
+                  },
+                  "required": {
+                    "type": "boolean"
+                  },
+                  "type": {
+                    "properties": {
+                      "kind": {
+                        "example": "string",
+                        "type": "string"
+                      }
+                    },
+                    "type": "object"
+                  }
+                },
+                "type": "object"
+              },
+              "type": "array"
+            },
+            "resourceType": {
+              "example": "id",
+              "type": "string"
+            },
+            "targetType": {
+              "example": "id",
+              "type": "string"
+            }
+          },
+          "type": "object"
+        },
+        "id": {
+          "example": "MyProjectId/workitems/epic",
+          "type": "string"
+        },
+        "links": {
+          "properties": {
+            "self": {
+              "example": "server-host-name/application-path/projects/MyProjectId/customfields/workitems/epic",
+              "type": "string"
+            }
+          },
+          "type": "object"
+        },
+        "meta": {
+          "properties": {
+            "errors": {
+              "items": {
+                "properties": {
+                  "detail": {
+                    "description": "Human-readable explanation specific to this occurrence of the problem.",
+                    "example": "Unexpected token, BEGIN_ARRAY expected, but was : BEGIN_OBJECT (at $.data)",
+                    "type": "string"
+                  },
+                  "source": {
+                    "properties": {
+                      "parameter": {
+                        "description": "String indicating which URI query parameter caused the error.",
+                        "example": "revision",
+                        "type": "string"
+                      },
+                      "pointer": {
+                        "description": "JSON Pointer to the associated entity in the request document.",
+                        "example": "$.data",
+                        "type": "string"
+                      },
+                      "resource": {
+                        "description": "Resource causing the error.",
+                        "properties": {
+                          "id": {
+                            "example": "MyProjectId/id",
+                            "type": "string"
+                          },
+                          "type": {
+                            "example": "type",
+                            "type": "string"
+                          }
+                        },
+                        "type": "object"
+                      }
+                    },
+                    "type": "object"
+                  },
+                  "status": {
+                    "description": "HTTP status code applicable to this problem.",
+                    "example": "400",
+                    "type": "string"
+                  },
+                  "title": {
+                    "description": "Short, human-readable summary of the problem.",
+                    "example": "Bad Request",
+                    "type": "string"
+                  }
+                },
+                "type": "object"
+              },
+              "type": "array"
+            }
+          },
+          "type": "object"
+        },
+        "type": {
+          "enum": [
+            "customfields"
+          ],
+          "type": "string"
+        }
+      },
+      "type": "object"
+    },
+    "included": {
+      "description": "Related entities might be returned, see <a href=\"https://docs.sw.siemens.com/en-US/doc/230235217/PL20250606201928474.polarion_help_sc.xid2134849/xid2134871\" target=\"_blank\">REST API User Guide</a>.",
+      "items": {
+        "type": "object"
+      },
+      "type": "array"
+    },
+    "links": {
+      "properties": {
+        "self": {
+          "example": "server-host-name/application-path/projects/MyProjectId/customfields/workitems/epic",
+          "type": "string"
+        }
+      },
+      "type": "object"
+    }
+  },
+  "type": "object"
+}

AddedSep 7, 2026

TDQS

A4.2/5.0

Behavior3/5

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safe-read profile is covered. The description adds the single-project scoping constraint, but says nothing about permissions, result ordering, or what happens when no custom fields are configured. Useful but thin beyond the annotations.

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?

Three short sentences, with the purpose and scope front-loaded and the routing hint last. No filler and nothing repeated.

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

Completeness4/5

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

With an output schema, full schema coverage, and read-only annotations, the description only needed to establish scope and sibling routing, which it does. Minor residual gap: it does not clarify how resourceType and targetType interact for custom fields, though the schema hints at this.

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 all six parameters are fully documented in the schema; baseline 3 applies. The description only echoes "resource type and target type" and adds no format, allowed-value, or defaulting guidance beyond what the schema already provides.

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

Purpose5/5

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

States a specific verb (Returns) and resource (defined Custom Fields), plus the exact scoping inputs (resource type, target type, project context). It also explicitly contrasts itself with the sibling getGlobalCustomFields, so an agent can distinguish the two without reading either schema.

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

Usage Guidelines5/5

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

Gives an explicit when-to-use condition (one project, requires a project ID) and names the alternative tool plus the condition that selects it ("To act across all projects, use getGlobalCustomFields instead"). Nothing is left to inference.

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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