CongressMCP-full

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Get Member Cosponsored Legislation - Bills and resolutions cosponsored by a member

get_member_cosponsored_legislation

Retrieve bills and resolutions cosponsored by a specific member of Congress using their bioguide ID. Supports pagination with limit and offset for browsing results.

Instructions

Get legislation cosponsored by a specific member of Congress.

Args:
    ctx: Context for API requests
    bioguide_id: Unique bioguide identifier for the member
    limit: Maximum number of cosponsored bills to return
    offset: Zero-based offset for pagination

Returns:
    List of bills and resolutions cosponsored by the member

Input Schema

TableJSON Schema

Name	Required	Description	Default
`limit`	No
`offset`	No
`bioguide_id`	Yes

Output Schema

TableJSON Schema

Name	Required	Description
`error`	No	Present when success is false: the section-9 error envelope
`items`	No	Results of other kinds (bills, reports, communications, nominations), as returned by Congress.gov
`context`	Yes	Context about the search or operation performed
`members`	No	Member results
`success`	Yes	Whether the operation was successful
`summary`	Yes	Human-readable summary of the results
`item_kind`	No	What `items` contains (bill, committee_report, communication, nomination, ...)
`operation`	Yes	The operation that was performed
`committees`	No	Committee results
`results_count`	Yes	Number of items returned (equals the populated list's length)

Schema Changelog

Changes observed during successful MCP inspections.

Changed34 schema fields changedv2.2.0Aug 26, 2026

addedOutput schema / $defs / CommitteeSummary / properties / chamber / anyOf

Added value: +[
+  {
+    "type": "string"
+  },
+  {
+    "type": "null"
+  }
+]

addedOutput schema / $defs / CommitteeSummary / properties / chamber / default
```
Added value: +null
```
removedOutput schema / $defs / CommitteeSummary / properties / chamber / type
```
Removed value: -"string"
```

changedOutput schema / $defs / CommitteeSummary / properties / committee_code / description

Previous value: -"Official committee code"New value: +"Official committee system code (e.g. hsju00)"

addedOutput schema / $defs / CommitteeSummary / properties / committee_type / anyOf

Added value: +[
+  {
+    "type": "string"
+  },
+  {
+    "type": "null"
+  }
+]

addedOutput schema / $defs / CommitteeSummary / properties / committee_type / default
```
Added value: +null
```

changedOutput schema / $defs / CommitteeSummary / properties / committee_type / description

Previous value: -"Type of committee (Standing, Select, etc.)"New value: +"Type of committee (Standing, Select, ...)"

removedOutput schema / $defs / CommitteeSummary / properties / committee_type / type
```
Removed value: -"string"
```
addedOutput schema / $defs / CommitteeSummary / properties / url / default
```
Added value: +null
```

changedOutput schema / $defs / CommitteeSummary / properties / url / description

Previous value: -"Congress.gov URL for committee details"New value: +"Congress.gov API URL for committee details"

changedOutput schema / $defs / CommitteeSummary / required

Previous value: -[
-  "committee_code",
-  "name",
-  "chamber",
-  "committee_type",
-  "url"
-]New value: +[
+  "committee_code",
+  "name"
+]

addedOutput schema / $defs / ErrorInfo

Added value: +{
+  "description": "Section-9 error payload: stable code, human message, secret-safe\ndetail, actionable remediation. Mirrors the bill-text tools' envelope\n(documentation/fulltext/04-tools-responses.md section 9).",
+  "properties": {
+    "code": {
+      "description": "Stable machine-readable error code (lowercase)",
+      "title": "Code",
+      "type": "string"
+    },
+    "detail": {
+      "anyOf": [
+        {
+          "additionalProperties": true,
+          "type": "object"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null,
+      "description": "Structured context; never carries secrets",
+      "title": "Detail"
+    },
+    "message": {
+      "description": "What went wrong",
+      "title": "Message",
+      "type": "string"
+    },
+    "remediation": {
+      "anyOf": [
+        {
+          "type": "string"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null,
+      "description": "What the caller should do about it",
+      "title": "Remediation"
+    }
+  },
+  "required": [
+    "code",
+    "message"
+  ],
+  "title": "ErrorInfo",
+  "type": "object"
+}

changedOutput schema / $defs / MemberSummary / description

Previous value: -"Summary information about a member of Congress."New value: +"Summary information about a member of Congress (list-level fields)."

addedOutput schema / $defs / MemberSummary / properties / chamber / anyOf

Added value: +[
+  {
+    "type": "string"
+  },
+  {
+    "type": "null"
+  }
+]

addedOutput schema / $defs / MemberSummary / properties / chamber / default
```
Added value: +null
```

changedOutput schema / $defs / MemberSummary / properties / chamber / description

Previous value: -"Chamber (House or Senate)"New value: +"Chamber of the member's most recent term"

removedOutput schema / $defs / MemberSummary / properties / chamber / type
```
Removed value: -"string"
```

addedOutput schema / $defs / MemberSummary / properties / current_member / anyOf

Added value: +[
+  {
+    "type": "boolean"
+  },
+  {
+    "type": "null"
+  }
+]

addedOutput schema / $defs / MemberSummary / properties / current_member / default
```
Added value: +null
```

changedOutput schema / $defs / MemberSummary / properties / current_member / description

Previous value: -"Whether this person is currently serving"New value: +"Whether currently serving (None if unknown)"

removedOutput schema / $defs / MemberSummary / properties / current_member / type
```
Removed value: -"boolean"
```
addedOutput schema / $defs / MemberSummary / properties / district / default
```
Added value: +null
```

changedOutput schema / $defs / MemberSummary / properties / district / description

Previous value: -"District number (for House members)"New value: +"District number (House members)"

addedOutput schema / $defs / MemberSummary / properties / party / default
```
Added value: +null
```
changedOutput schema / $defs / MemberSummary / properties / party / description
```
Previous value: -"Political party (D, R, I)"New value: +"Political party"
```
addedOutput schema / $defs / MemberSummary / properties / state / default
```
Added value: +null
```
addedOutput schema / $defs / MemberSummary / properties / url / default
```
Added value: +null
```

changedOutput schema / $defs / MemberSummary / properties / url / description

Previous value: -"Congress.gov URL for member details"New value: +"Congress.gov API URL for member details"

changedOutput schema / $defs / MemberSummary / required

Previous value: -[
-  "bioguide_id",
-  "name",
-  "party",
-  "state",
-  "district",
-  "chamber",
-  "current_member",
-  "url"
-]New value: +[
+  "bioguide_id",
+  "name"
+]

changedOutput schema / description

Previous value: -"Response from the members and committees tool."New value: +"Response from the members and committees tools.\n\nSome operations return items that are neither members nor committees\n(a member's sponsored bills, a committee's reports/communications/\nnominations); those arrive in `items` as the API's own dicts, labeled\nby `item_kind`."

addedOutput schema / properties / error

Added value: +{
+  "anyOf": [
+    {
+      "$ref": "#/$defs/ErrorInfo"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "description": "Present when success is false: the section-9 error envelope"
+}

addedOutput schema / properties / item_kind

Added value: +{
+  "anyOf": [
+    {
+      "type": "string"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "description": "What `items` contains (bill, committee_report, communication, nomination, ...)",
+  "title": "Item Kind"
+}

addedOutput schema / properties / items

Added value: +{
+  "default": [],
+  "description": "Results of other kinds (bills, reports, communications, nominations), as returned by Congress.gov",
+  "items": {
+    "additionalProperties": true,
+    "type": "object"
+  },
+  "title": "Items",
+  "type": "array"
+}

changedOutput schema / properties / results_count / description

Previous value: -"Number of results returned"New value: +"Number of items returned (equals the populated list's length)"

Changed1 schema field changedv2.1.0Aug 21, 2026
- addedInput schema / properties / offset
```
Added value: +{
+  "default": 0,
+  "title": "Offset",
+  "type": "integer"
+}
```
First observedv2.0.0Apr 3, 2026

TDQS

A4.1/5.0

Behavior3/5

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

No annotations are present, so the description carries more weight. It discloses the read-only nature through the verb 'Get' and the 'Returns' section, and it exposes pagination behavior via offset and limit. However, it does not explicitly confirm no side effects, mention permissions, or describe any error/rate-limit behavior.

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?

The description is compact, well-organized into Args and Returns sections, and the core purpose is front-loaded in the first sentence. Every section earns its place with no filler or repetition.

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?

For a simple read-only lookup, the description is nearly complete: all user-supplied parameters are described and the output schema covers return shape. The main gap is that it doesn't explicitly route the agent to get_member_sponsored_legislation when sponsored bills are needed, and the mention of 'ctx' might be slightly confusing since it is not in the input schema.

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

Parameters5/5

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

The input schema has 0% property descriptions, but the description fully compensates by explaining all three parameters: bioguide_id is the unique member identifier, limit is the maximum number of bills, and offset is zero-based pagination. This adds meaningful semantics beyond the raw JSON schema.

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 opens with 'Get legislation cosponsored by a specific member of Congress,' which names a specific verb, resource, and scope. The use of 'cosponsored' clearly distinguishes this from sibling tool get_member_sponsored_legislation.

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?

The description implies the tool should be used when the agent needs bills/resolutions cosponsored by a particular member, but it does not explicitly state when to use this tool versus alternatives like get_member_sponsored_legislation. There are no exclusions or when-not-to-use conditions.

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