Polarion MCP Server

getProjectCustomFields

Read-only

Retrieve custom field definitions for a resource type and target type within a Polarion project. Provide a project ID to scope the query to that project.

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

TableJSON Schema

Name	Required	Description
`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; call getProjects to list valid IDs.
`targetType`	Yes	Identifies the target resource type this operation applies to (e.g. `workitem`). Use `~` (no quotes) to mean no specific target type.
`resourceType`	Yes	The Resource Type.

Output Schema

TableJSON 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.

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

A4.5/5.0

Behavior4/5

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

The description adds context beyond the annotations: it highlights the project-scoping requirement and directs to the global alternative. While annotations already declare readOnlyHint=true, the description's explicit scope constraint and sibling reference provide useful behavioral context that the annotations alone do not cover.

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 with no filler. The primary purpose is stated first, followed by the scope constraint and the alternative. Every sentence earns its place and the structure is clean and front-loaded.

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

Completeness5/5

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

With an output schema present, annotations covering the read-only/open-world behavior, and 100% parameter descriptions, the description only needs to clarify the distinguishing project scope and the sibling alternative. It does exactly that, making it complete for correct invocation.

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 input schema fully documents all five parameters. The description adds little parameter-level meaning beyond echoing 'resource type and target type' and noting the project ID requirement, which is already in the schema. A baseline of 3 is appropriate.

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?

The description states a specific verb and resource ('Returns the defined Custom Fields') and the context ('for the resource type and target type in the Project context'). It explicitly differentiates from the sibling getGlobalCustomFields, making the tool's purpose unambiguous and immediately distinguishable.

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?

The description explicitly states the scope ('one project (requires a project ID)') and names the alternative for cross-project scenarios ('use getGlobalCustomFields instead'). This gives clear when-to-use and when-not-to-use guidance, leaving nothing 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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