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

Annotations already declare a safe read operation, and the description adds genuinely new semantics: a null limit means unlimited on this plan, and pricing is deliberately excluded. It does not cover auth requirements or any pagination/refresh behavior, but for a zero-argument plan lookup those gaps are minor.

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-loaded with the resource and its contents, followed by usage triggers and two boundary clauses; almost every clause carries information. The first sentence is long and densely list-like, which slightly taxes readability but nothing is filler.

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 full burden of describing return content, and it does so field-by-field (allowances, usage counts, slots) plus the null-means-unlimited convention. Nothing an agent needs to call or interpret this tool 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?

The tool takes no arguments, so per the rubric the baseline is 4; there is nothing for the description to clarify beyond the schema's own 'This tool takes no arguments.'

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 states a specific resource (the workspace's current plan) and enumerates exactly what it reports: DM usage against the monthly allowance, extra messages purchased, Instagram account and live-campaign allowances vs. usage, and knowledge base/flow slots. An agent can distinguish it from account_ai_credits or account_instagram_accounts because those cover single counters while this is the consolidated limits view.

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?

Explicit when-to-use is given: any question about limits, what is left, whether something is about to run out, or why HookSend stopped sending. It also draws one boundary (pricing belongs on the customer's billing page), but names no sibling alternative for overlapping questions, so it stops short of a 5.

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