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

Annotations already declare readOnlyHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered; the description adds real context beyond that by disclosing scope exclusions ('No payment details') and where mutations must happen ('plans are changed in the OsmO app'). It doesn't discuss caching, freshness, or what happens when forwarding is misconfigured, which keeps it below a 5.

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?

A single sentence front-loads the resource ('The user's OsmO account') then lists contents, closing with the read-only caveat and the out-of-band alternative. The comma-separated field list is dense but every item earns its place; it could have been split for scannability.

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 describing the return payload and does so field by field, plus it clarifies what is deliberately excluded. For a zero-parameter read-only tool, an agent has everything needed to decide to call it and interpret the result.

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; baseline 4 applies. The enumerated return fields are a bonus, not required parameter guidance.

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?

Specific verb+resource: it names the account status and enumerates exactly which fields come back (plan and renewal/trial end, assistant name, forwarding number, forwarding health, last screening check, call counts today/this week). That distinguishes it from list/lookup siblings, though it doesn't explicitly separate it from overlapping tools like get_settings or get_assistant.

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?

It gives one useful routing hint — plans are changed in the OsmO app, implying this tool is read-only inspection rather than configuration. There is no explicit statement of when to prefer this over get_settings or get_assistant, so usage is only implied.

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