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

Annotations already declare readOnlyHint=true, so the description adds useful context beyond that: results are scoped to accounts the user belongs to (permission-filtered), each row includes phone numbers and role, and the underlying endpoint is GET /accounts. Ordering, page size, and whether an empty list is an error are not covered.

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 sentences, front-loaded with the purpose, then the highest-value fact (other tools need a slug from here), then the endpoint. Zero 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?

For a simple no-required-param list tool with no output schema, the description does tell the agent what comes back (phone numbers, role, and implicitly the slug it needs downstream). Pagination is handled by the schema, so nothing critical is missing, though the shape/field names of results are only loosely described.

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?

There is one optional parameter and the schema fully documents it, including how to obtain the cursor value from `view.next`. The description adds nothing about the cursor, so the baseline of 3 applies when the schema does the work.

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?

Names a specific verb and resource ('List the TextUs accounts') and adds scope ('the user belongs to') plus returned fields (phone numbers, role). It does not explicitly distinguish itself from the sibling textus_get_account, so an agent must infer that one is single-account retrieval and the other is enumeration.

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?

'Most other tools need an account `slug` from here' is a genuine routing hint that tells the agent to call this first as a discovery step. No explicit exclusions or when-not conditions are stated (e.g., versus textus_get_account when the slug is already known).

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