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

The readOnlyHint annotation already covers the safety profile, so the 'Read only' sentence is partly redundant, but the description adds genuine context by describing what the response carries (quantity, price, per-status delivery counts) in the absence of any output schema. It also scopes the meaning of 'campaign' as a grouped send. It does not mention rate limits or ordering, which keeps it short of 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?

Three short, front-loaded sentences with no filler; the resource and its contents lead, followed by the read-only caveat and the endpoint. The telegraphic noun-phrase opening is compact but slightly clipped compared to a full verb-phrase statement.

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 7-parameter, zero-required listing tool with no output schema, the description covers purpose, returned fields, and safety context, while the schema fully documents filters, pagination, and defaults. Nothing essential is missing, though a note on result ordering or the relationship to smsmode_get_campaign would have closed the last gap.

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 description coverage is 100%, so every parameter (page, status, dates, page_size, channel_id, ref_client) is already documented, including the pagination hint about next_page and the default date window. The description adds no format or syntax detail beyond restating the status enum values, so the baseline 3 applies.

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 names the specific resource ('SMS campaigns (grouped sends)') and clarifies the domain term, then enumerates what each record contains (status values, quantity, price, delivery counts). It is distinguishable from smsmode_get_campaign (plural listing vs. single fetch) and from smsmode_list_messages, though it never explicitly contrasts itself with those siblings. The only weakness is that it is a noun phrase rather than containing its own verb.

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 only implied: 'Read only: this server does not send campaigns' signals that smsmode_send_sms is a different concern, but there is no explicit when-to-use guidance or routing to smsmode_get_campaign for a single campaign. An agent can infer the listing intent from the name and schema, but nothing tells it when this tool is preferred over its siblings.

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