List my series

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so safety is covered. The description adds rich behavioral context: it requires an API key, is unfiltered and unpaginated, returns a specific structure `{ series, total }` with detailed per-entry fields, and defines empty-list semantics ('not an error'). This goes well beyond the annotations and fully discloses behavior.

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 concise despite containing multiple pieces of information. Each sentence serves a purpose: purpose, clarification of name, use cases, behavioral details, and return format. It is front-loaded with the main action and flows logically. No filler or redundancy.

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?

Given the tool has zero parameters and no output schema, the description goes beyond the minimum by defining the exact return shape and edge-case behavior (empty list). It also covers authentication, rendering it fully self-contained. The agent has everything needed to select and invoke the tool 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?

Input schema has zero parameters (100% coverage). Baseline for zero params is 4, but the description adds valuable context by stating 'takes no parameters — it is unfiltered and unpaginated.' This explicitly prevents the agent from attempting to pass filters or pagination, which is meaningful for correct invocation. Thus it exceeds the baseline.

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: 'List every series the authenticated account owns.' It further distinguishes itself from a single-series lookup by explicitly noting that despite the name, it returns the whole collection and that there is no single-series lookup. This clearly differentiates from sibling tools like create_series and add_to_series.

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 provides explicit when-to-use guidance: 'Use it to find a series slug before calling add_to_series, or to check whether a series already exists before create_series makes a duplicate.' It also clarifies the read-only nature, telling the agent it can be safely used for lookups without side effects. No exclusions are needed, making this highly actionable.

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