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

Annotations already declare readOnly/non-destructive, and the description adds substantial context beyond them: how a slot is deemed free, timezone fallback behavior (`effective_timezone` is UTC when none is saved), the `move_posts_past_limits` default-on setting, and the equivalent REST endpoint.

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?

Front-loads the return value and the primary usage directive, with no filler sentences; the parenthetical asides about timezone and the settings flag are dense but each carries real information, though the long compound sentences could be split for readability.

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 carries the burden of explaining return values and does so (saved daily times plus `next_slots` as UTC timestamps), and it covers timezone semantics and the limit-handling setting, leaving nothing an agent needs before calling it.

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 `count` and `workspace_id` are already documented in the schema; the description adds contextual meaning about what the workspace's queue represents but no extra syntax or format detail for the parameters themselves. Baseline 3 applies when the schema does the heavy lifting.

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 ('Returns the user's saved daily posting times for a workspace') plus the derived `next_slots` output, and implicitly distinguishes itself from the write-side sibling update_posting_slots by describing a read of the queue.

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?

Explicitly says when to use it ('Use this before scheduling instead of guessing a time') and names the concrete alternative path ('pass use_next_slot: true to schedule_post / batch_schedule_posts'), so the agent knows both the trigger and the downstream consumer.

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