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

The description substantially discloses behavioral traits beyond the readOnlyHint annotation: it lists exactly what will be reported (both address forms, subaccount, permissions) and explicitly states what it 'CANNOT' do, such as withdraw, create wallets, reveal keys/mnemonics, or switch accounts. This helps an agent understand the tool as safe and non-mutating. It aligns with the readOnlyHint, so there is no contradiction.

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 description is dense but well-organized: front-loaded with the action ('Report what this session controls'), then detailed specific outputs, then explicit can't-do list, then a terse 'Call this first' usage tip. Every sentence carries useful information, including the clarifying parenthetical 'the same 20 bytes.'

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 no-parameter introspection tool with no output schema, the description doubles as an effective output contract. It describes almost all necessary return facets: account addresses in two formats, subaccount, trading capability, authorization scope, and explicit negations. This is complete enough for an agent to invoke and interpret the result without ambiguity.

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 has zero parameters and the schema reflects this completely. Per baseline, 0 parameters means no descriptive burden. The description doesn't need to add parameter semantics, and it doesn't attempt to invent inputs.

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 clearly identifies the tool's purpose with a specific verb and resource: 'Report what this session controls.' It enumerates the exact contents (master account in both cosmos/EV M forms, subaccount, trade/read-only status, auth scope, permissions). This distinguishes it from all siblings by establishing it as session introspection, not market data or trading.

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 gives explicit usage context: 'Call this first, and use it to answer what is my address?.' This tells an agent when to invoke it, though it does not explicitly discuss exclusions or alternatives. Since there are no sibling tools that obviously duplicate this introspection role, concise context is sufficient.

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