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

With no annotations at all, the description carries the full burden. It does useful work by implying a read-only listing, promising result ordering, and clarifying via "The website posts them by itself" that invoking this tool does not publish anything. It leaves unstated what "approved" means, whether results are paginated, and what each post entry contains.

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 with no filler, front-loaded with the action and scope. The final sentence about the website posting on its own earns its place by removing a likely agent misconception.

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, parameterless list tool this covers scope and ordering adequately, but with no output schema the description should hint at what a post record contains and whether the list can be large. Those gaps keep it at minimum-viable rather than 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?

The tool takes zero parameters, so there is nothing for the description to disambiguate beyond the implicit filter, which it does state clearly (approved, today or later). Baseline 4 applies for a parameterless tool.

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 ("List ... Instagram post") plus the filtering scope (approved, dated today or later) and ordering guarantee. The agent can distinguish this from get_next_post only by inference, since no sibling is named explicitly, so it falls short of a 5.

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?

Usage is implied rather than stated: the "today or later" filter and the note that the website publishes on its own suggest this is for inspection, not scheduling. There is no explicit when-to-use/when-not-to-use guidance and no reference to get_next_post as the single-item alternative.

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