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

Annotations already declare a safe read-only/idempotent profile, and the description layers on genuinely non-obvious behavior: the enforced 1-hour gap between posts, preferred-hours respect, the America/New_York timezone default, and the 7-day ranking window with 1-5 stars and a per-slot reason. This is exactly the context annotations cannot convey.

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?

Four tight sentences, front-loaded with the purpose and constraints before the strategy detail. The inline quoting of strategy "best_engagement" is slightly awkward, but no sentence is wasted.

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?

With no output schema, the description still tells the agent what a slot contains (UTC instant to pass as scheduled_at, star rating, reason), which is the key return-value detail. It leaves out the shape of non-ranked slots and the role of workspace_id, minor gaps for a 5-parameter read tool.

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 60%, and the description compensates for the uncovered gaps: it warns that timezone has a hidden America/New_York default and must be set explicitly, and that account_ids is mandatory for best_engagement. workspace_id remains unexplained in both schema and description, which keeps it from a 5.

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 + resource ('Find available time slots for posting') and immediately scopes it with the constraints that define the result (1-hour gap, preferred hours). Clearly distinguishable from creation siblings like create_post or listing siblings like list_posts.

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 explicit operational guidance: always pass timezone explicitly (with the default named), and best_engagement requires account_ids. This selects between the two strategy modes. It does not, however, mention when to use this tool versus alternatives such as get_post or validate_post, or when scheduling is inappropriate.

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