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

The description adds substantial behavior beyond annotations: values are stored in memory only, omitted fields are preserved across calls, credentials are per-session, `apiUrl` may be fixed on hosted servers, no auth is required to set auth material, and errors occur only for structural invalidity. This strongly complements the idempotentHint and non-read-only annotations without contradicting them.

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?

Six compact sentences cover action, storage model, env-var alternative, platform constraint, auth requirement, error behavior, and next step. Every sentence earns its place, and the most important operational fact is front-loaded.

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?

The description is complete enough for an optional-parameter configuration tool: it explains scope, merging, constraints, auth, error behavior, and the correct next tool. The only minor gap is that no success response/return value is described, though the error statement partially compensates since there is no output schema.

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?

Schema coverage is 100%, and each parameter already has detailed descriptions including examples, secret warnings, and mode implications. The tool description adds relevant session-level semantics like merge-on-partial-call, but does not need to restate per-parameter meaning; baseline 3 is appropriate.

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 and resource: 'Set the Ethora API URL and credentials for this MCP session.' It clearly differentiates itself from the auth-use siblings by framing configuration as establishing auth material that is later selected by an `ethora-auth-use-*` tool.

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 explicitly states when to use this tool versus env vars, notes the hosted-server constraint on `apiUrl`, and gives a direct follow-up instruction: 'Follow with an `ethora-auth-use-*` tool to pick the active mode.' This gives an agent actionable selection and sequencing guidance.

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