MCP Tool Discovery: Read the Catalog Before Asking an Agent to Act

An assistant says it can upload a video, research competitors, and publish a campaign through your content platform. Before accepting the plan, inspect the tool catalog. A plausible description of a workflow is not evidence that the connected service exposes every operation in it.

MCP tool discovery gives the client information about what a server offers. The useful habit is to read that information as a contract: names, descriptions, schemas, permissions, and results. For Caroush, the public catalog is a starting point, while the authenticated connection and its grant determine what the client can actually use.

Separate the public reference from the authenticated tool list

A public reference can describe the server's implemented capabilities without granting access to them. The authenticated list can be narrower because of approved scopes, account conditions, or other server rules. Seeing a tool in documentation does not mean your connection is entitled to invoke it.

The MCP tools specification describes tools/list and tools/call, including pagination and tool metadata. A client should use the protocol's actual listing behavior instead of guessing capabilities from a server name.

Caroush publishes a tool reference and a downloadable schema catalog. Compare those documents with the tools exposed to the connection. If an operation is absent, first investigate the documented permission requirements rather than assuming the server is broken.

The Caroush MCP landing section helps users choose a setup path, but a client selector is not a capability inventory. The catalog and verified connection provide the stronger evidence.

Read a tool definition in a useful order

Start with the description of the effect. Does the operation read data, save a draft, queue generation, request an approval, or change an existing object? Similar names can represent materially different consequences.

Next, read required inputs and allowed values. Determine which identifiers must refer to existing owned objects and which fields are optional. A tool that accepts media IDs does not necessarily accept file uploads or arbitrary URLs.

Then inspect the result contract. A returned request identifier with a queued status calls for follow-up. An approval URL represents a review boundary. A saved draft object demonstrates creation, not publication.

Finally, read the scope and any plan or provider constraints. For Caroush, normal generation credits and quotas still apply, and saved analytics requires the documented eligible plan. The tool list does not erase those business rules.

This order keeps the inspection practical: effect, input, result, and authority. It is easier to use than reading a large schema top to bottom without first understanding the operation's purpose.

Use the catalog to challenge invented workflow steps

Suppose an assistant proposes to call a tool named request_upload_link, send it a video URL, and publish the returned object to every platform. That plan should stop at the catalog review. Caroush's verified catalog does not establish such an upload-link tool or a generic arbitrary-URL upload workflow.

A supported create_image_post operation references existing owned media IDs. Direct TikTok publishing through MCP is rejected in Caroush's documented boundaries. The reviewed composer is the appropriate path for that destination. These details change the workflow before any request is sent.

Likewise, a general research step may require a separate browsing capability or human-supplied sources. Caroush's content tools should not be described as a built-in web-research service without evidence.

For a team using an AI post generator, this is a valuable distinction: the assistant may help plan a broader process, but each external action must map to a real supported capability or an explicit manual handoff.

Distinguish protocol primitives from service features

MCP can expose tools, resources, and prompts, as explained in the architecture guide. That protocol vocabulary does not mean every server implements every primitive or that a business feature with a similar name uses a particular primitive.

For example, a product record might be returned through a read tool. Calling it “context” in ordinary language does not establish that it appears as an MCP resource. Similarly, a caption-generation tool is not automatically a reusable MCP prompt template.

This distinction helps avoid configuration errors. A client should discover and use the capabilities the server declares. It should not invent a resource URI because a blog article said MCP supports resources in general.

For Caroush, focus first on the documented tool interface and the actual task. If the workflow is carousel generation, identify the operation, required product context, result-following path, and review boundary. Do not add unrelated protocol features simply to make the integration sound more complete.

Treat annotations as hints with a trust boundary

Tool metadata can help a client display or reason about operations, but annotations are not an independent guarantee that a tool is harmless. The tools specification warns clients to treat annotations as untrusted unless they come from trusted servers.

A read-only hint should be considered alongside the server identity, description, schema, and verified behavior. It does not remove the risk that returned content exposes sensitive data or contains misleading instructions. A tool with a harmless name can still request broad access if the server is untrusted.

For an internal review, ask who operates the server and where its documentation comes from. Confirm that the endpoint matches the expected service rather than an unrelated proxy with a familiar label. Maintain the same caution when adding a new server that you would apply to another application receiving business access.

A social media content audit examines the quality and relevance of published material. A tool-catalog review examines what the assistant can do to the workspace. They support different decisions and should not be substituted for one another.

Keep a small capability map for the real workflow

You do not need to memorize the entire catalog. Build a short map of the operations the team's current task requires. Include the tool name, required context, expected result, scope, and whether the action needs browser approval.

For a text-draft pilot, that map might contain workspace confirmation and draft creation. For a later scheduling handoff, add the documented scheduling operation and its approval requirement. Keep these as separate workflow stages so a change in responsibility is visible.

When an operation is missing from the authenticated list, compare the grant with the public reference. When a schema changes, update the specific workflow mapping rather than rewriting every team instruction. When a client caches an old list, refresh it through its supported behavior before concluding that the server removed a feature.

Version and date the map. The catalog is a living contract, and a screenshot from an earlier release may be inaccurate. A concise current reference is more useful than a long list of speculative capabilities.

Accept a plan only when every external step has a route

Before running a multi-step task, ask the assistant to identify which steps use supported tools, which need review, and which remain manual. This makes the plan concrete enough to evaluate without requesting broad new permissions prematurely.

If the plan includes an undocumented operation, revise it before execution. If a tool returns an unfamiliar state, consult the result contract rather than translating it into a reassuring sentence. If the connection lacks a required permission, decide whether the task actually needs that capability.

A good catalog review does not slow down useful work. It removes imaginary steps early, preserves clear approval boundaries, and gives the team an evidence-based understanding of what its AI connection can accomplish today.

For example, a launch plan can label its first step as retrieving authorized product context, its second as saving a draft, and its third as a human review. If a later publication request is appropriate, identify that tool and its approval separately. This small map makes unsupported claims easy to spot: a proposed analytics comparison needs an available read tool and eligible account, while a web-research step needs its own source-gathering route. Each step should produce an inspectable artifact or decision. A plan that only names broad outcomes such as “optimize engagement” has not yet demonstrated that the catalog can carry out the work.