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

Goes beyond the annotations by stating the side effect precisely: 'Creates data in the account (nothing is sent to anyone),' which usefully disambiguates the openWorldHint=true flag for a create operation. It stops short of covering non-idempotency consequences (calling twice likely yields two lists with the same name) or any permission requirements.

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?

Front-loaded with the core action and scope, then side effects, then field kinds — ordered by importance. Tight overall; the trailing 'POST /lists' is a minor implementation detail that doesn't help an agent decide or call the tool.

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 an 8-parameter create tool with no output schema, the description covers purpose, side effects, and field kinds well, but never says what comes back (e.g., the new list's identifier needed for subsequent lead operations) or what defaults apply when columns is omitted — the latter is only hinted in the 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 description coverage is 100%, so the schema already documents name, columns, the category strings, and the field-kind enum, making 3 the baseline. The description's recital of field kinds and 'none (text)' / 'text (multi-line)' clarifications largely restates the enum documentation rather than adding new meaning.

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?

Specific verb + resource + scope: 'Create a new, empty calling list with its fields,' which clearly separates it from siblings like myphoner_create_lead, myphoner_list_lists, and myphoner_get_list. 'Empty' is a meaningful qualifier telling the agent no leads are added here.

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?

Usage is only implied: the tool creates a list, so it presumably precedes lead creation/moves, but the description never says when to call this versus myphoner_create_lead or how it relates to an existing list retrieved via myphoner_get_list. No exclusions or prerequisites (e.g., name uniqueness) are given.

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