list_scheduled_posts

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

The description adds valuable context beyond the readOnlyHint annotation: it explicitly discloses that scheduling/publishing/deleting is NOT performed by this server, preventing the agent from assuming this tool can schedule posts. It also clarifies the read-only nature with 'Read-only visibility into what's queued.' The readOnlyHint already covers the safety profile, and the description reinforces it with concrete scoping.

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?

Three concise sentences with zero waste. Front-loaded with the primary purpose, immediately clarifies scope boundaries (what it doesn't do), and lists the return fields. Every sentence 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 simple read-only list tool with 100% schema coverage, full param documentation, a strong readOnlyHint annotation, and clear scope disambiguation from siblings, the description is complete. It explains what it returns, the ordering, what it does NOT do, and its relationship to the broader system.

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 coverage is 100%, so both parameters (limit, offset) are already fully documented in the schema with their defaults and clamping behavior. The description adds the list ordering ('soonest first') which is useful context, but doesn't add significant param semantics beyond what the schema provides. Baseline 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?

Specific verb+resource: 'List posts scheduled for future publication, soonest first.' Clearly distinguishes from siblings like list_published_posts and list_drafts by focusing on scheduled/future posts. States exactly what is returned (id, title, audience, trigger_at).

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 explicitly notes 'scheduling itself is done in Substack's editor' and that 'this server does not schedule, publish, or delete long-form posts,' which disambiguates from create/update tools. It also clarifies this is read-only visibility into the queue. A clear alternative is implicitly established via the sibling list_published_posts, though it doesn't explicitly name the alternative tool for publishing.

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