mcp-walmart-marketplace
Click on "Deploy Server".
Wait a few minutes for the server to deploy. Once ready, it will show a "Started" state.
In the chat, type
@followed by the MCP server name and your instructions, e.g., "@mcp-walmart-marketplacefetch my open orders and their statuses"
That's it! The server will respond to your query, and you can continue using it as needed.
Here is a step-by-step guide with screenshots.
Walmart Marketplace APIs
MCP server for Walmart Marketplace APIs — items, orders, inventory, prices, promotions, feeds, reports, returns, fulfillment, and more.
Exposes spec-driven discovery (list_endpoints, describe_endpoint), a generic API proxy (call_endpoint), feed upload and file download helpers, and a runtime spec refresher (refresh_specs). The AI agent discovers endpoints from bundled OpenAPI specs then calls them; the server handles OAuth2 token acquisition, refresh, and Walmart's required headers automatically. Base addresses are hardcoded per environment, so the config file carries nothing but credentials.
Features
Spec-driven discovery — 28 bundled OpenAPI specs covering 234 operations, refreshable at runtime
Any endpoint — call by operation id or raw method+path; no code changes when APIs evolve
Automatic OAuth2 — tokens fetched, cached per credential, refreshed before expiry, retried once on 401. The client secret never leaves token acquisition
Multi-advertiser — many seller credentials per region and environment, selected per call
Multi-region, multi-environment — production and sandbox
Required Walmart headers (
WM_SEC.ACCESS_TOKEN,WM_SVC.NAME,WM_QOS.CORRELATION_ID,WM_MARKET,WM_GLOBAL_VERSION,WM_SANDBOX,WM_PARTNER_ID) injected server-side and hidden from the agentLarge responses truncated with full data available via MCP resource URI
Related MCP server: MoySklad MCP Server
Requirements
Python 3.13+
Walmart Marketplace client ID and client secret per seller (Developer Portal)
Quick start
Set up your config (see Configuration), then run the server:
# Run directly with uvx (no clone needed)
npx -y @modelcontextprotocol/inspector uvx mcp-walmart-marketplace# Or run from source
git clone https://github.com/alyiox/mcp-walmart-marketplace.git
cd mcp-walmart-marketplace
uv sync
npx -y @modelcontextprotocol/inspector uv run mcp-walmart-marketplaceConfiguration
The config file lives under your home directory at ~/.config/mcp-walmart-marketplace/config.json.
Windows note:
~maps to%USERPROFILE%, so the full path is%USERPROFILE%\.config\mcp-walmart-marketplace\config.json.
1. Create the config directory and copy the example
mkdir -p ~/.config/mcp-walmart-marketplace
cp config.example.json ~/.config/mcp-walmart-marketplace/config.json2. Edit ~/.config/mcp-walmart-marketplace/config.json
{
"response_cache_ttl": 3600,
"truncate_threshold": 1024,
"regions": {
"primary": {
"production": {
"credentials": [
{
"client_id": "11111111-2222-3333-4444-555555555555",
"client_secret": "acme-client-secret-goes-here",
"advertisers": [
{ "id": 1000001, "partner_id": "10000000001" },
{ "id": 1000002 }
]
}
]
},
"sandbox": {
"credentials": [
{
"client_id": "aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee",
"client_secret": "acme-sandbox-client-secret-goes-here",
"advertisers": [{ "id": 1000001 }]
}
]
}
}
}
}Config field | Description |
| Seconds to keep truncated responses in memory (default |
| Response byte limit before truncation (default |
| Region label — case-insensitive, free-form. Groups advertisers; it does not change which host is called |
| Environment — exactly |
| One entry per Walmart client credential |
| Walmart client ID (UUID) |
| Walmart client secret, as plain text |
| Sellers this credential serves, each |
Keep the config file readable only by you — it holds client secrets in plain text.
Everything else is fixed by the server: base URLs (marketplace.walmartapis.com for production, sandbox.walmartapis.com for sandbox), WM_SVC.NAME, the client_credentials grant, and the per-operation WM_MARKET / WM_SANDBOX header values.
Regions
A region is a namespace, not a route. Base addresses are fixed by the server per environment, so every region reaches the same Walmart hosts. The level exists so advertiser ids only have to be unique within one region — the same id under two regions can mean different sellers with different credentials.
Partner IDs
Add partner_id to a seller that has a Walmart Partner ID:
"advertisers": [
{ "id": 1000001, "partner_id": "10000000001" },
{ "id": 1000002 }
]Two payments operations — payments:getTaxForms and payments:downloadTaxForm — require it as the WM_PARTNER_ID header. Calling one for a seller configured without a partner id fails with a message telling you to add it, rather than a Walmart 400. Every other operation ignores it, so most entries are just {"id": …}.
Advertisers
advertiser_id is required on every tool that reaches the network; there is no default. Read the wmm://config resource to discover which advertiser ids are configured. It reports region, environment, and advertiser ids only — never client ids or secrets.
Tools
Tool | Purpose |
| List operations across the bundled specs, filtered by query, domain, tag, or method |
| One operation plus its schema closure, with server-managed headers stripped |
| Execute any operation by id or raw method+path |
| Upload a feed file (multipart) for a feed type |
| Download a report, label, or other binary to a local path |
| Re-pull specs from the ReadMe api-registry into the user cache |
Resources
URI | Contents |
| Configured regions, environments, and advertiser ids |
| Full body of a truncated response |
| Equivalent cURL command for a previous request |
MCP host examples
Cursor
Add to .cursor/mcp.json:
{
"mcpServers": {
"walmart-marketplace": {
"command": "uvx",
"args": ["mcp-walmart-marketplace"]
}
}
}Claude Code
Add to your Claude Code MCP config:
{
"mcpServers": {
"walmart-marketplace": {
"command": "uvx",
"args": ["mcp-walmart-marketplace"]
}
}
}Codex
[mcp_servers.walmart-marketplace]
command = "uvx"
args = ["mcp-walmart-marketplace"]OpenCode
{
"$schema": "https://opencode.ai/config.json",
"mcp": {
"walmart-marketplace": {
"type": "local",
"enabled": true,
"command": ["uvx", "mcp-walmart-marketplace"]
}
}
}GitHub Copilot
{
"inputs": [],
"servers": {
"walmart-marketplace": {
"type": "stdio",
"command": "uvx",
"args": ["mcp-walmart-marketplace"]
}
}
}Specs
The 28 bundled specs come from the ReadMe api-registry that backs
developer.walmart.com. They load from the user cache dir first
(~/.cache/mcp-walmart-marketplace/specs/) and fall back to the copy shipped in
the wheel, so refresh_specs takes effect immediately without a reinstall.
The files on disk are stored verbatim as the registry served them, so the bundle is the source of truth and a refresh diff shows exactly what Walmart changed. Reduction happens on load, which keeps it a runtime policy rather than something baked into the files:
Oversized examples are dropped. There are 3,514 inline
examplepayloads totalling 4.13 MB, but the median is 16 bytes and two/v3/items/taxonomypayloads account for 3.25 MB. Everything at or underMAX_EXAMPLE_BYTES(1 KB) survives — 97% of them, for ~133 KB — so format hints for dates, skus, and identifiers stay available while the monsters never reach an agent.x-readmeis removed — docs-platform rendering metadata, not API detail.
Cost of loading all 28 specs is ~80 ms once per process; results are cached per
spec and invalidated by file mtime, so a refresh_specs takes effect
immediately. describe_endpoint output is 5.1 KB at the median and 88 KB at the
worst (six order-management operations inline very large response schemas).
To rebuild the bundled copies:
uv run python scripts/fetch_specs.py # all
uv run python scripts/fetch_specs.py order-managementCaveats
The specs and the API disagree about authentication. 76 operations declare a Basic Authorization header built from the client id and secret, and fulfillment-management and insights-management appear to require it instead of an access token. Probed against production, that is wrong: Basic alone returns 401, the access token alone returns 200, on every service tested. This server therefore sends WM_SEC.ACCESS_TOKEN on every request and never sends the client secret anywhere except /v3/token. If you diff its behavior against the reference docs, that gap is deliberate.
WM_SVC.NAME cannot be read from the specs. 103 operations declare the literal placeholder string "Walmart Service Name" and only 100 the real value, so it is fixed at Walmart Marketplace, which live calls confirm.
Not every documented endpoint is reachable with seller credentials. GET /v3/utilities/apiStatus returns HTTP 520 Unable to route request, naming wm_svc.name: PARTNERMANAGEMENTSERVICES and wm_svc.env: prod as the expected headers — but sending exactly those still returns 520. It appears to belong to a service that 3P credentials cannot reach, and the error message is a red herring. Expect a handful of similar cases across 234 operations.
Report endpoints negotiate content strictly. They reject Accept: */* with a 406 listing what they can produce, so Accept is derived from the media types the operation declares for its success responses (preferring application/json when offered). If you add an endpoint whose spec declares no response content, it falls back to */* and may 406.
Live coverage is thin. Seven operations across five domains have returned 200 against production — feed-management, advertising, fulfillment-management, insights-management, settings-management — including two report downloads that arrive as real Excel workbooks. The other ~227 are wired from the specs and have never been called. Discovery and request construction are covered by tests; upstream behavior is not.
Two known upstream failures, neither a client bug: fulfillment-management:getInventoryHealthReport answers 520 WFS_INTERNAL_SERVER_ERROR, and feed-management:getFeedErrorReport answers 404 for a feed that processed cleanly.
Sandbox is unverified. Walmart issues sandbox credentials separately from production, and nothing here has run against sandbox.walmartapis.com. The WM_SANDBOX: v2 handling — which opts into the dynamic sandbox and changes response semantics rather than just routing — is implemented from the specs, not observed.
upload_feed is untested end to end. It is exercised by unit tests against a scripted transport only — the sole way to verify it live is to submit a real feed, which mutates a live catalog. download_file has been verified against production.
The cross-host redirect path is unexercised. download_file sheds credentials when a redirect leaves Walmart's host, which matters if a report is ever served from signed storage. Every download observed so far returned its bytes directly, in one hop, so that branch has only unit-test coverage.
License
MIT
Available Tools
6 toolscall_endpointADestructive
[WalmartMarketplace] Execute an authenticated API request. Give operation_id, or method and path together. Auth, WM_MARKET, WM_GLOBAL_VERSION, WM_SANDBOX and correlation headers are added by the server.
| Name | Required | Description | Default |
|---|---|---|---|
| body | No | [WalmartMarketplace] JSON request body for POST/PUT/PATCH. | |
| path | No | [WalmartMarketplace] API path after the base URL, e.g. /v3/orders. Required unless operation_id is given. | |
| method | No | [WalmartMarketplace] HTTP method. Required unless operation_id is given. | |
| params | No | [WalmartMarketplace] Query string parameters as a JSON object. | |
| region | Yes | [WalmartMarketplace] Region label, e.g. us. Src: config. | |
| environment | Yes | [WalmartMarketplace] Target environment — production or sandbox. Src: config. | |
| path_params | No | [WalmartMarketplace] Values for {placeholders} in the path, e.g. {"purchaseOrderId": "1796277083022"}. | |
| operation_id | No | [WalmartMarketplace] Operation id as domain:operationId. Resolves method, path, and required headers from the spec. Src: operations. | |
| advertiser_id | Yes | [WalmartMarketplace] Advertiser (seller profile) id to act as. Required — selects the credential. Src: config. |
Output Schema
| Name | Required | Description |
|---|---|---|
| body | No | |
| curl | No | |
| error | No | |
| cached_at | No | |
| truncated | No | |
| status_code | No |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare destructiveHint=true and readOnlyHint=false, so the agent knows this can modify or delete data. The description adds that authentication headers are injected by the server, which is useful but does not elaborate on side effects or risk. Since the annotation already covers the main behavioral traits, the description adds modest context but could explicitly warn about potential for mutations or irreversible actions.
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?
The description is only two sentences, tightly packed with the essential information: the tool is an authenticated API caller, accepts either operation_id or method+path, and that auth headers are server-managed. Every sentence earns its place, and the primary guidance is front-loaded. No fluff or redundancy.
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?
The tool has nine parameters and an output schema, which covers return values. The description does not address error handling, pagination, or response format, but the output schema likely handles that. However, it lacks guidance on preferred usage (e.g., using operation_id when available vs raw path) and does not mention that it can call any endpoint in the spec, which could be helpful for agent decision-making. Given the schema's richness, this is adequate but not exceptional.
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 all nine parameters are already documented in the input schema. The description repeats the relationship between operation_id and method/path, which is also captured in the schema. It provides no additional parametric detail or syntax beyond what the schema offers, so the baseline of 3 is appropriate.
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?
The description clearly states the tool's purpose: 'Execute an authenticated API request' and specifies the two invocation modes (operation_id or method+path). This distinguishes it from sibling tools like list_endpoints and upload_feed, which are more specialized. The verb 'Execute' and resource 'authenticated API request' are specific and unambiguous.
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?
The description explains how to invoke the tool (operation_id or method+path) but provides no guidance on when to use this tool versus alternatives such as upload_feed or describe_endpoint. It does not mention any exclusions or scenarios where a sibling would be more appropriate, leaving the agent to infer that this is the low-level fallback without explicit direction.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
describe_endpointARead-only
[WalmartMarketplace] Describe one OpenAPI operation with its schema closure. Returns the operation plus every components.schemas entry reachable from it, so request bodies and responses can be built without the full spec. Server-managed auth and QoS headers are omitted — do not supply them.
| Name | Required | Description | Default |
|---|---|---|---|
| operation_id | Yes | [WalmartMarketplace] Operation id, qualified as domain:operationId (e.g. order-management:getAllOrders). Src: operations. |
Output Schema
| Name | Required | Description |
|---|---|---|
No output parameters | ||
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description adds behavioral context beyond annotations: it states that server-managed auth and QoS headers are omitted and instructs not to supply them, and it explains the output (operation plus reachable schemas). Since annotations already mark readOnlyHint=true, this extra detail is valuable and doesn't contradict.
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?
The description is two sentences, front-loaded with the core function, followed by concrete output description and a clear instruction. No unnecessary words.
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?
Given the existence of an output schema and the read-only annotation, the description covers what the tool returns, the intended use case, and an important behavioral note about headers. Nothing critical is missing for an agent to call it correctly.
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?
The schema provides a full description of the operation_id parameter with format and example, so the tool description adds no additional parameter semantics. With 100% schema description coverage, the baseline of 3 is appropriate.
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?
The description clearly states the tool's purpose: to describe an OpenAPI operation and its schema closure. It specifies the verb 'describe', the resource (an OpenAPI operation), and the additional detail of returning reachable schemas. This distinguishes it from siblings like list_endpoints (listing) and call_endpoint (calling).
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?
The description implies a usage scenario: when you need to understand the schema of an endpoint to build request bodies and responses without the full spec. However, it does not explicitly compare with alternatives or state when not to use it, so it's clear context but lacks explicit exclusions.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
download_fileARead-only
[WalmartMarketplace] Download a report, label, or other binary payload to a local path. Give a full url, or operation_id (or method and path). Follows redirects and drops credentials when a redirect leaves Walmart's host.
| Name | Required | Description | Default |
|---|---|---|---|
| url | No | [WalmartMarketplace] Absolute URL to fetch, e.g. a report URL returned by a previous call. | |
| path | No | [WalmartMarketplace] API path when not using url. | |
| method | No | [WalmartMarketplace] HTTP method when using path. | |
| params | No | [WalmartMarketplace] Query string parameters. | |
| region | Yes | [WalmartMarketplace] Region label, e.g. us. Src: config. | |
| dest_path | Yes | [WalmartMarketplace] Local path to write the downloaded bytes to. | |
| environment | Yes | [WalmartMarketplace] Target environment — production or sandbox. Src: config. | |
| path_params | No | [WalmartMarketplace] Values for {placeholders} in path. | |
| operation_id | No | [WalmartMarketplace] Operation id as domain:operationId. Src: operations. | |
| advertiser_id | Yes | [WalmartMarketplace] Advertiser (seller profile) id to act as. Src: config. |
Output Schema
| Name | Required | Description |
|---|---|---|
| path | No | |
| urls | No | |
| error | No | |
| status_code | No | |
| content_type | No | |
| bytes_written | No |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate readOnlyHint=true, so the read-only nature is covered. The description adds valuable behavioral context: it follows redirects and drops credentials when redirecting away from Walmart's host. This goes beyond the annotations and informs the agent of security-relevant behavior.
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?
The description is two sentences with zero waste. The primary purpose is stated first, followed by essential behavioral detail about redirects. Every sentence earns its place and the structure is front-loaded.
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?
For a download tool with 10 parameters and read-only annotations, the description covers the key usage scenarios and security behavior. It does not mention output schema or file handling details, but the presence of an output schema and the tool's straightforward nature make this acceptable. Overall, it is complete enough for correct invocation.
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 parameters have individual descriptions. The tool description adds value by clarifying the relationship between url, operation_id, and method/path (i.e., you can use one of these alternatives), which is not evident from the schema alone. However, it does not add syntax or format details beyond that.
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?
The description clearly states the action (download), the resource type (report, label, or other binary payload), and the destination (local path). It also lists multiple ways to specify the target (full url, operation_id, or method+path), making the tool's purpose distinct from siblings like call_endpoint which are for API calls.
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?
The description explains how to invoke the tool (via url, operation_id, or method+path) but does not explicitly contrast it with sibling tools or state conditions for when to choose this over call_endpoint or upload_feed. The context of binary payload download is implied but not made explicit against alternatives.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
list_endpointsBRead-only
[WalmartMarketplace] List OpenAPI operations with optional filters.
| Name | Required | Description | Default |
|---|---|---|---|
| tag | No | [WalmartMarketplace] Filter to operations whose OpenAPI tags include this value. | |
| query | No | [WalmartMarketplace] Case-insensitive substring match on operation id, path, or summary. | |
| domain | No | [WalmartMarketplace] Limit to one API domain, e.g. order-management. Src: specs. | |
| method | No | [WalmartMarketplace] Filter by HTTP verb — GET, POST, PUT, PATCH, DELETE. |
Output Schema
| Name | Required | Description |
|---|---|---|
No output parameters | ||
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and openWorldHint=false, so the tool is known to be read-only with a bounded scope. The description adds the concept of 'optional filters' but does not disclose any additional behavioral traits such as sorting, pagination, or the format of the returned list. Given the annotation coverage, a score of 3 is appropriate – the description provides minimal added behavioral context.
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?
The description is a single, concise sentence that is front-loaded with the domain context ('[WalmartMarketplace]') and immediately states the core action and resource. There is zero redundancy or wasted words, making it highly scannable for an agent.
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?
Given the tool's simplicity (read-only, all parameters optional and documented, output schema present), the description is quite complete. It could arguably mention that it returns a list of operations or that it is a discovery tool, but the output schema covers the return structure, and the tool's purpose is clear. The only minor gap is lack of explicit guidance on when to use it, but that is more about usage guidelines than contextual completeness of the operation itself.
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?
The input schema provides 100% coverage with detailed descriptions for all four parameters (tag, query, domain, method). The description's mention of 'optional filters' adds no new meaning beyond what the schema already specifies. Baseline 3 is correct because the schema does the heavy lifting; the description does not enhance parameter understanding.
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?
The description states a specific verb ('List') and resource ('OpenAPI operations'), and mentions optional filters, which clearly conveys the tool's purpose. It is distinguishable from siblings like 'describe_endpoint' and 'call_endpoint' by the action and resource, though it does not explicitly name those alternatives.
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?
The description provides no guidance on when to use this tool versus the sibling tools (e.g., 'describe_endpoint', 'call_endpoint'). It does not mention that it is a discovery tool for finding operations before calling them, nor does it state any exclusions or alternatives. The agent must infer usage from the name and parameters.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
refresh_specsAIdempotent
[WalmartMarketplace] Refresh bundled OpenAPI specs from the public registry into the user cache, which then takes precedence over the bundled copies.
| Name | Required | Description | Default |
|---|---|---|---|
| spec_id | No | [WalmartMarketplace] Refresh only this spec, e.g. order-management. Omit to refresh all. Src: specs. |
Output Schema
| Name | Required | Description |
|---|---|---|
No output parameters | ||
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate a non-read-only, idempotent, non-destructive write. The description adds that the refresh comes from the public registry and that the cache takes precedence over bundled copies, which directly informs the agent of the effect on subsequent tool calls. This goes beyond the annotation baseline and clarifies the behavioral impact.
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?
A single, front-loaded sentence conveys the entire purpose and key constraint. Every word contributes meaning; there is no redundancy or filler. The description efficiently sets expectations without unnecessary elaboration.
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?
For such a simple tool with one optional parameter and a full schema description, the description covers everything needed: what it refreshes, where it refreshes from, and the precedence effect. The output schema exists, and no other behavioral aspects are missing, making the definition complete.
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?
The sole parameter spec_id is fully described in the schema (including an example and the 'omit to refresh all' behavior), so the schema provides complete coverage. The tool description does not add any additional parameter detail, which is appropriate given the high schema coverage.
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?
The description states a specific action (refresh bundled OpenAPI specs) with a clear source (public registry) and destination (user cache). It also notes the behavioral consequence that the cache takes precedence over bundled copies, which clearly distinguishes it from the sibling tools that list, describe, or call endpoints.
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?
The description implies when to use the tool—when you want to update cached spec definitions—but it does not explicitly state alternatives or when not to use it. No exclusions or routing guidance are provided, so an agent must infer appropriate usage from the tool name and siblings.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
upload_feedA
[WalmartMarketplace] Upload a feed file for a feed type. Posts the local file as multipart/form-data to /v3/feeds and returns the feed id.
| Name | Required | Description | Default |
|---|---|---|---|
| region | Yes | [WalmartMarketplace] Region label, e.g. us. Src: config. | |
| feed_type | Yes | [WalmartMarketplace] Walmart feedType, e.g. MP_ITEM, MP_INVENTORY, RETIRE_ITEM. Valid values are enumerated on each domain's POST /v3/feeds operation. Src: operations. | |
| file_path | Yes | [WalmartMarketplace] Local path of the feed file to upload. | |
| environment | Yes | [WalmartMarketplace] Target environment — production or sandbox. Src: config. | |
| advertiser_id | Yes | [WalmartMarketplace] Advertiser (seller profile) id to act as. Src: config. |
Output Schema
| Name | Required | Description |
|---|---|---|
| body | No | |
| curl | No | |
| error | No | |
| cached_at | No | |
| truncated | No | |
| status_code | No |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already set readOnlyHint=false and destructiveHint=false, so the description's mention of 'Upload' is consistent and adds no contradiction. The description does add behavioral context beyond annotations by specifying the HTTP method (multipart/form-data) and the endpoint ('/v3/feeds'), as well as the return value (feed id). It does not disclose potential side effects like asynchronous processing or rate limits, but these may be covered by the openWorldHint annotation. Overall, this is adequate but not rich.
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?
The description is a single, focused sentence that front-loads the purpose and includes the essential technical details (multipart/form-data, endpoint, return value). There is no redundant or vague phrasing; every clause earns its place.
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?
For a mutation tool with 5 required parameters, all fully described in the schema, and an output schema present, the description is nearly complete. It covers the action, method, endpoint, and return value. It does not explicitly mention prerequisites like file accessibility or that the operation may be asynchronous, but these are either implied ('local path') or not critical for invocation. The description fills the essential gaps left by the schema.
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 every parameter has a documented description in the schema. The tool description does not add any extra meaning beyond restating 'feed file' and 'feed type'; it does not elaborate on parameter formats, constraints, or relationships. Since the schema already handles parameter documentation, a baseline of 3 is appropriate.
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?
The description clearly states the action ('Upload a feed file'), the resource ('for a feed type'), and the specific mechanism ('Posts the local file as multipart/form-data to /v3/feeds'). It also tells the caller the key result ('returns the feed id'). This is distinct from siblings which handle endpoint listing, generic calling, or downloads, so there's no ambiguity.
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?
The description implies usage context (uploading a feed file) but does not explicitly state when to prefer this over other tools or provide exclusions. There is no mention of alternatives or conditions like 'use call_endpoint for non-feed operations'. However, the tool's specificity (multipart feed upload) makes the intent clear enough for most agents.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Tool Schema Changelog
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
6 tool updates
v0.1.0- First observed
call_endpoint - First observed
describe_endpoint - First observed
download_file - First observed
list_endpoints - First observed
refresh_specs - First observed
upload_feed
TDQS
Scored across 6 tools
Each tool has a clearly distinct purpose: listing/describing endpoints for discovery, calling endpoints for execution, uploading feeds, refreshing specs, and downloading binaries. No overlapping responsibilities that could cause misselection.
All tool names follow a consistent verb_noun pattern in snake_case (list_endpoints, describe_endpoint, call_endpoint, upload_feed, refresh_specs, download_file). The convention is uniform and predictable.
With 6 tools, the server is well-scoped for its purpose of interfacing with a large external API. Each tool earns its place, covering discovery, generic execution, and targeted conveniences without redundancy or bloat.
The call_endpoint tool provides generic access to all Walmart Marketplace operations, ensuring no dead ends. The other tools handle spec discovery, feed uploads, and binary downloads, covering the full lifecycle without significant gaps.
Maintenance
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