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

Annotations already cover the read-only/idempotent/non-destructive profile, but the description adds substantially more: default and max page size, sort order, the fact that this read is NOT gated by the Send Message module, and that a 403 here should be investigated rather than attributed to a disabled module. That error-semantics guidance is exactly the kind of behavior 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?

Front-loads purpose and pagination before the boundary/error guidance, and most sentences earn their place. However, sentences 4-6 restate the same 'creation is intentionally unsupported' point three times, including a maintainer attribution and a repeat of the do-not-hallucinate instruction, which could be tightened.

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 read-only list tool with full schema coverage and no output schema, nothing an agent needs is missing: filters and pagination are described, ordering is stated, unsupported operations are called out, and the 403 failure mode is pre-empted. The boundary guidance is unusually complete.

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% with enums for status, channel, and category, so the schema documents every parameter including defaults and bounds. The description only restates pagination defaults (25/100), adding no syntax or format meaning beyond the schema, 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?

States a specific verb and resource ('List the account email and SMS campaigns'), plus ordering ('newest first') and scope ('with filters and pagination'). It is clearly distinguishable from the singular get_campaign and the write siblings pause/resume/cancel_campaign that it names.

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 enumerates the category's capabilities and boundaries: reads only, creation unavailable, and the alternative for creation is named (the Sweeppea app). It also tells the agent how to respond when a user asks for an unsupported action, which is stronger than a simple use/don't-use statement.

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