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

Aligns perfectly with annotations (read-only, idempotent, non-destructive) and adds new context: requires API key, no parameters, unfiltered and unpaginated, and empty list is not an error. This enriches the agent's understanding beyond annotations.

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?

Every sentence serves a purpose: purpose, clarification, usage, behavior, return format, and edge-case handling. The structure flows logically from what → when → how, with no 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?

For a parameterless tool with no output schema, the description covers all necessary context: what it does, when to use, return shape, and error semantics. No gaps remain for an agent to misinfer.

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?

With zero parameters and 100% schema coverage, the baseline is 4; the description goes further by explicitly stating it takes no parameters and explaining the implications (no filtering/pagination). This adds semantic value beyond the schema.

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 states the tool lists all series owned by the authenticated account, and explicitly clarifies that despite the name it returns the whole collection, not a single series. This distinguishes it from other series-related tools and eliminates ambiguity.

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 use cases: finding a series slug before add_to_series, or checking existence before create_series to avoid duplicates. It also notes there is no single-series lookup, guiding agents away from misusing it.

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