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

Annotations already declare readOnly, idempotent, non-destructive behavior, so the safety bar is low. The description adds genuinely useful context beyond that: default date window, oldest-first ordering, the full set of returned fields, and the plan-gated upgrade-message failure mode.

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 dense but well-ordered sentences, front-loaded with the core action and date window, then tacked-on filtering and the plan caveat. Nearly every clause carries information, though the returned-field list makes it slightly heavy.

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 read-only, fully-schematized list tool with annotations covering safety and no output schema, the description is nearly complete: it discloses the default range, ordering, field payload, optional filter, and the upgrade-gated failure mode. Only explicit sibling routing is missing.

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 from/to defaults and the tag_id UUID are already documented and the baseline is 3. The description restates the date defaults and clarifies tag_id filters to posts carrying one tag, adding marginal meaning over the schema without new syntax or format detail.

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 gives a specific verb ('Get') and resource ('every post scheduled between two dates'), plus scope, ordering, and returned fields. The phrase 'the content calendar view' frames it distinctly from the bulk listing siblings like list_posts, though no sibling is named explicitly to confirm the boundary.

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?

'Needs a plan that includes the content calendar; otherwise it returns an upgrade message' is a useful prerequisite, and the default window is stated. However, it never says when to reach for this over list_posts, fetch_content_feed, or list_drafts, so routing between calendar and listing tools is left to inference.

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