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

Annotations already carry the safety profile (readOnlyHint, idempotentHint, destructiveHint=false), so the bar is lower. The description adds real value beyond that: it explains portals are public client-facing pages where viewers comment/vote without an account, and it discloses the exact return shape (ids, name, url, flow ids, settings, plan limit), which is essential given there is no output schema.

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?

Two tight sentences, front-loaded with the action and resource before the definitional context. Every clause earns its place, since the portal definition and return shape are the only way an agent learns this domain concept without an output schema.

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 parameters, no output schema, and rich annotations, the description supplies exactly what is missing: what a portal is and what the call returns. An agent has everything needed to invoke it correctly.

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 the baseline is 4. Nothing about parameter syntax is needed, and the description correctly adds no misleading parameter detail.

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 (List) and resource (client portals of the user), then defines what a portal actually is. An agent can instantly distinguish this read-only listing from siblings like save_portal, delete_portal, and get_share_status.

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?

The description implies usage by scoping to the user's own portals and providing domain context, but never states when to use this versus sibling read/portal tools (e.g., get_flow or get_share_status). No explicit alternatives or exclusions, so the guidance stays at the 'implied' tier.

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