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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so safety is covered; the description adds two things beyond that: which post statuses are included (draft, scheduled, publishing) and a hard return cap of 50 posts. It does not say whether the cap truncates silently or how to page past it, which is the remaining behavioral gap.

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 short sentences, zero redundancy, with the core purpose and the result cap both front-loaded. Every clause carries information the agent needs.

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 list with fully described parameters and no output schema, the description covers purpose, filters and result size adequately. The only omission is what happens at the 50-post boundary (truncation vs. pagination), which matters for an agent deciding whether the result is 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?

Schema description coverage is 100%, so defaults for from/to and the platform enum (including the twitter-is-X note) are already fully documented in the schema. The description only restates "optional network filter and date range" without adding format or edge-case semantics, so baseline 3 applies.

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 and resource ("lists ... posts") plus the scope (draft, scheduled and publishing posts on the calendar). It is clearly a read/list operation distinct from siblings like schedule_post or publish_now, though it never names an alternative explicitly.

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 phrase "on the calendar" plus the default-from-now window implies the calendar/upcoming use case, but there is no explicit statement of when to use this instead of schedule_post, generate_post, or a hypothetical full post list. Usage is inferable rather than stated.

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