list_entities

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint false. The description adds valuable behavioral detail: it states that `token_configured` only indicates whether the env var is set and non-blank, and never reveals the value, which is important for security-sensitive agents. The 'No Mercury request' note further clarifies the tool's operational behavior, going beyond the annotation safety profile.

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 compact—three sentences that front-load the primary purpose, then provide routing guidance, and finally a security-relevant note about token_configured. Every sentence earns its place with no redundancy or fluff.

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 parameterless list tool, the description is complete: it states the output fields, the primary use case, differentiates from siblings, and discloses a non-obvious behavior (token_configured never reveals the value). An output schema exists to detail the return structure, so the description does not need to repeat that. No gaps are evident.

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 are zero parameters, so the schema trivially covers everything. The baseline for 0-parameter tools is 4. The description does not add parameter-specific semantics (none needed), but it does clarify what the returned fields mean, which is helpful for interpreting results.

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 opens with a specific verb-resource statement ('List the configured Mercury organizations') and enumerates the output fields (entity keys, display names, token configuration). It explicitly differentiates from sibling tools by naming `server_info` and `get_org` as alternatives for other purposes, so an agent can immediately recognize what this tool does and what it does not.

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 a clear use case ('find the entity key the Mercury tools require') and explicitly directs the agent to `server_info` for build info and `get_org` for the legal profile, establishing when to use this tool versus alternatives. It also clarifies that no Mercury request is made, so the agent knows it is a lightweight local read.

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