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

With no annotations, the description carries the full burden and usefully discloses the 'ungated' access condition (works for all users including Free/vault-only), which an agent needs to know before recommending it. It does not describe return behavior, but the presence of an output schema lowers that burden.

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?

The core capability and its routing preference are front-loaded, and the trigger list, while long, directly serves selection. Slightly list-heavy but every line earns its place.

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 zero-parameter, output-schema-backed discovery tool, the description covers what it returns, when to prefer it over the sibling, who can call it, and the intents that map to it. Nothing an agent needs to call it correctly is missing.

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 and there is nothing for the description to compensate for. No semantic gap exists.

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 object ('Show everything on the user's TigerTiger plan — tools, trigger phrases, and how sessions work') and immediately differentiates from the sibling help tool by naming cos.help() as the alternative. An agent can distinguish this from 'help' or 'my_account' without opening a schema.

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 names the alternative ('Preferred over cos.help() for plan-wide questions') and supplies the selecting condition plus an enumerated set of trigger phrases covering the exact user intents this should serve. Routing is unambiguous.

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