set_usernameSet the signed-in user’s public Synoptic username to a saved suggestion or their verified X handle. Generate suggestions first when needed.
| Name | Required | Description | Default |
|---|---|---|---|
| username | Yes | One of the latest generate_username_suggestions results or the verified X handle (xComHandle in get_me), matched exactly; other values are rejected |
| Name | Required | Description | Default |
|---|---|---|---|
| user | Yes |
Changes observed during successful MCP inspections.
Output schema / properties / user / properties / medalsCountRemoved value: -{
- "type": "number"
-}Output schema / properties / user / requiredPrevious value: -[
- "id",
- "username",
- "fullName",
- "createdAt",
- "followingCount",
- "followersCount",
- "medalsCount",
- "isHighlighted"
-]New value: +[
+ "id",
+ "username",
+ "fullName",
+ "createdAt",
+ "followingCount",
+ "followersCount",
+ "isHighlighted"
+]Output schema / properties / user / properties / avatar / anyOfPrevious value: -[
- {
- "additionalProperties": false,
- "properties": {
- "bucket": {
- "description": "S3 bucket holding the image",
- "minLength": 1,
- "type": "string"
- },
- "height": {
- "anyOf": [
- {
- "exclusiveMinimum": 0,
- "type": "integer"
- },
- {
- "type": "null"
- }
- ],
- "description": "Height in pixels"
- },
- "key": {
- "description": "Storage key of the image",
- "minLength": 1,
- "type": "string"
- },
- "region": {
- "description": "AWS region of the bucket",
- "minLength": 1,
- "type": "string"
- },
- "type": {
- "description": "MIME type, such as image/png",
- "minLength": 1,
- "type": "string"
- },
- "width": {
- "anyOf": [
- {
- "exclusiveMinimum": 0,
- "type": "integer"
- },
- {
- "type": "null"
- }
- ],
- "description": "Width in pixels"
- }
- },
- "required": [
- "bucket",
- "key",
- "region",
- "type"
- ],
- "type": "object"
- },
- {
- "type": "null"
- }
-]New value: +[
+ {
+ "additionalProperties": false,
+ "properties": {
+ "bucket": {
+ "minLength": 1,
+ "type": "string"
+ },
+ "height": {
+ "anyOf": [
+ {
+ "exclusiveMinimum": 0,
+ "type": "integer"
+ },
+ {
+ "type": "null"
+ }
+ ]
+ },
+ "key": {
+ "minLength": 1,
+ "type": "string"
+ },
+ "region": {
+ "minLength": 1,
+ "type": "string"
+ },
+ "type": {
+ "description": "MIME type, such as image/png",
+ "minLength": 1,
+ "type": "string"
+ },
+ "width": {
+ "anyOf": [
+ {
+ "exclusiveMinimum": 0,
+ "type": "integer"
+ },
+ {
+ "type": "null"
+ }
+ ]
+ }
+ },
+ "required": [
+ "bucket",
+ "key",
+ "region",
+ "type"
+ ],
+ "type": "object"
+ },
+ {
+ "type": "null"
+ }
+]Output schema / properties / user / properties / backgroundImage / anyOfPrevious value: -[
- {
- "additionalProperties": false,
- "properties": {
- "bucket": {
- "description": "S3 bucket holding the image",
- "minLength": 1,
- "type": "string"
- },
- "height": {
- "anyOf": [
- {
- "exclusiveMinimum": 0,
- "type": "integer"
- },
- {
- "type": "null"
- }
- ],
- "description": "Height in pixels"
- },
- "key": {
- "description": "Storage key of the image",
- "minLength": 1,
- "type": "string"
- },
- "region": {
- "description": "AWS region of the bucket",
- "minLength": 1,
- "type": "string"
- },
- "type": {
- "description": "MIME type, such as image/png",
- "minLength": 1,
- "type": "string"
- },
- "width": {
- "anyOf": [
- {
- "exclusiveMinimum": 0,
- "type": "integer"
- },
- {
- "type": "null"
- }
- ],
- "description": "Width in pixels"
- }
- },
- "required": [
- "bucket",
- "key",
- "region",
- "type"
- ],
- "type": "object"
- },
- {
- "type": "null"
- }
-]New value: +[
+ {
+ "additionalProperties": false,
+ "properties": {
+ "bucket": {
+ "minLength": 1,
+ "type": "string"
+ },
+ "height": {
+ "anyOf": [
+ {
+ "exclusiveMinimum": 0,
+ "type": "integer"
+ },
+ {
+ "type": "null"
+ }
+ ]
+ },
+ "key": {
+ "minLength": 1,
+ "type": "string"
+ },
+ "region": {
+ "minLength": 1,
+ "type": "string"
+ },
+ "type": {
+ "description": "MIME type, such as image/png",
+ "minLength": 1,
+ "type": "string"
+ },
+ "width": {
+ "anyOf": [
+ {
+ "exclusiveMinimum": 0,
+ "type": "integer"
+ },
+ {
+ "type": "null"
+ }
+ ]
+ }
+ },
+ "required": [
+ "bucket",
+ "key",
+ "region",
+ "type"
+ ],
+ "type": "object"
+ },
+ {
+ "type": "null"
+ }
+]Input schema / properties / username / descriptionAdded value: +"One of the latest generate_username_suggestions results or the verified X handle (xComHandle in get_me), matched exactly; other values are rejected"Output schema / properties / user / properties / avatar / anyOfPrevious value: -[
- {
- "additionalProperties": false,
- "properties": {
- "bucket": {
- "minLength": 1,
- "type": "string"
- },
- "height": {
- "anyOf": [
- {
- "exclusiveMinimum": 0,
- "type": "integer"
- },
- {
- "type": "null"
- }
- ]
- },
- "key": {
- "minLength": 1,
- "type": "string"
- },
- "region": {
- "minLength": 1,
- "type": "string"
- },
- "type": {
- "minLength": 1,
- "type": "string"
- },
- "width": {
- "anyOf": [
- {
- "exclusiveMinimum": 0,
- "type": "integer"
- },
- {
- "type": "null"
- }
- ]
- }
- },
- "required": [
- "bucket",
- "key",
- "region",
- "type"
- ],
- "type": "object"
- },
- {
- "type": "null"
- }
-]New value: +[
+ {
+ "additionalProperties": false,
+ "properties": {
+ "bucket": {
+ "description": "S3 bucket holding the image",
+ "minLength": 1,
+ "type": "string"
+ },
+ "height": {
+ "anyOf": [
+ {
+ "exclusiveMinimum": 0,
+ "type": "integer"
+ },
+ {
+ "type": "null"
+ }
+ ],
+ "description": "Height in pixels"
+ },
+ "key": {
+ "description": "Storage key of the image",
+ "minLength": 1,
+ "type": "string"
+ },
+ "region": {
+ "description": "AWS region of the bucket",
+ "minLength": 1,
+ "type": "string"
+ },
+ "type": {
+ "description": "MIME type, such as image/png",
+ "minLength": 1,
+ "type": "string"
+ },
+ "width": {
+ "anyOf": [
+ {
+ "exclusiveMinimum": 0,
+ "type": "integer"
+ },
+ {
+ "type": "null"
+ }
+ ],
+ "description": "Width in pixels"
+ }
+ },
+ "required": [
+ "bucket",
+ "key",
+ "region",
+ "type"
+ ],
+ "type": "object"
+ },
+ {
+ "type": "null"
+ }
+]Output schema / properties / user / properties / avatar / descriptionAdded value: +"Profile image; null when none is set"Output schema / properties / user / properties / backgroundImage / anyOfPrevious value: -[
- {
- "$ref": "#/properties/user/properties/avatar/anyOf/0"
- },
- {
- "type": "null"
- }
-]New value: +[
+ {
+ "additionalProperties": false,
+ "properties": {
+ "bucket": {
+ "description": "S3 bucket holding the image",
+ "minLength": 1,
+ "type": "string"
+ },
+ "height": {
+ "anyOf": [
+ {
+ "exclusiveMinimum": 0,
+ "type": "integer"
+ },
+ {
+ "type": "null"
+ }
+ ],
+ "description": "Height in pixels"
+ },
+ "key": {
+ "description": "Storage key of the image",
+ "minLength": 1,
+ "type": "string"
+ },
+ "region": {
+ "description": "AWS region of the bucket",
+ "minLength": 1,
+ "type": "string"
+ },
+ "type": {
+ "description": "MIME type, such as image/png",
+ "minLength": 1,
+ "type": "string"
+ },
+ "width": {
+ "anyOf": [
+ {
+ "exclusiveMinimum": 0,
+ "type": "integer"
+ },
+ {
+ "type": "null"
+ }
+ ],
+ "description": "Width in pixels"
+ }
+ },
+ "required": [
+ "bucket",
+ "key",
+ "region",
+ "type"
+ ],
+ "type": "object"
+ },
+ {
+ "type": "null"
+ }
+]Output schema / properties / user / properties / backgroundImage / descriptionAdded value: +"Profile background image; null when none is set"Output schema / properties / user / properties / followersCount / descriptionAdded value: +"Users following this user"Output schema / properties / user / properties / followingCount / descriptionAdded value: +"Users this user follows; excludes streams"Output schema / properties / user / properties / id / descriptionAdded value: +"Synoptic user ID for follow_user, is_following_user or get_user_by_id"Output schema / properties / user / properties / isHighlighted / descriptionAdded value: +"Featured by Synoptic; listed by get_highlighted_authors"Output schema / properties / user / properties / xComHandle / descriptionAdded value: +"Verified X handle linked to this profile, without @"Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare this as a non-read-only, destructive, idempotent, open-world mutation, so the safety profile is covered structurally. The description adds useful auth scope (it always targets the signed-in user, not an arbitrary user) but does not say what the destructive change entails — whether the previous username is released, whether it is publicly visible or subject to uniqueness/collision failure.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two sentences, no filler: the action and its value constraints come first, the prerequisite tool second. Nothing to trim.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
With an output schema present, return values need no explanation, and the description covers scope, allowed inputs, and the sibling dependency for a one-param mutation. The remaining gap is the outcome of a destructive identity change (old handle fate, failure on taken names), which agents would benefit from knowing before calling.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%, so the single param's exact-match and rejected-value semantics are already documented in the schema. The description restates the same two allowed sources rather than adding format, casing, or uniqueness rules beyond what the schema gives.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
States a specific verb and resource ('Set the signed-in user's public Synoptic username') and constrains the value domain to two named sources: a saved suggestion or the verified X handle. That scope also separates it cleanly from the sibling generate_username_suggestions, which only produces candidates.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Names the prerequisite tool explicitly ('Generate suggestions first when needed') and implies the X-handle path requires verification (see get_me). The phrase 'when needed' is soft — it does not say the suggestion route is required before a first-time set, nor that values outside the two sources are rejected (that lives only in the schema).
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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