save_post

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

No annotations are provided, so the description carries the full burden, and it delivers: it discloses the remote-then-local write pattern, that confirmation comes from Substack's save API or a best-effort button click, and the meaning of remote_confirmed=False (locally cached but unverified). It also names the remediation ('sync --force'), which is exactly the kind of behavioral context an agent needs for a mutation tool.

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?

Front-loads the core action, then the auth prerequisite, then the confirmation semantics in a logical order. It is slightly long and the confirmation-mechanism detail is dense, but every sentence conveys actionable behavior rather than filler.

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?

An output schema exists, so return values need no explanation. Combined with the auth requirement, local-vs-remote semantics, and failure/remediation behavior, the description covers everything an agent needs to invoke this 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?

Schema description coverage is 0% and there is one required 'url' parameter with no type/format guidance in the schema. The description partially compensates by noting the post's numeric ID is read from the page, implying the input is a post page URL, but it never specifies whether a full URL, slug, or ID is expected.

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 (bookmark/save) and resource (Substack post) plus the dual scope: remote on Substack and local cache. An agent can immediately distinguish it from unsave_post and save_note, which operate on different actions or resources.

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?

Gives a clear prerequisite and recovery path: requires an authenticated Substack session and tells the agent to run 'substack-saved-mcp login' if expired. It implies the save-vs-unsave dichotomy via naming but never states an explicit when-not or names an alternative tool.

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