get_event_ancestors

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

With no annotations provided, the description carries the full burden. It discloses the return structure (a dict with 'count' and 'ancestors') and clarifies that ancestors are ordered paths. While it does not cover edge cases like invalid IDs, the behavior is straightforward and well-explained for a read-only retrieval.

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 and well-structured with clear Args and Returns sections. It states the core purpose in one sentence, followed by the parameter explanation and return format—no redundant or extraneous content.

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's simplicity (one required parameter, no output schema), the description provides complete contextual information: what it does, what the parameter means, and what the response will contain. The agent has everything needed to invoke it correctly.

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?

The schema only defines 'stable_id' as a string with no description. The tool description adds essential meaning: that it is an 'Event (pathway or reaction) stable id' and provides a concrete example ('R-HSA-69620'). This fully compensates for the 0% schema coverage.

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 states a specific verb ('Retrieve') and resource ('all paths from an event up to its top-level pathway(s)'), clearly distinguishing it from sibling tools like get_event_participants or find_pathways_for_entity. The breadcrumb use case further clarifies its unique role.

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 notes it is 'Useful for building breadcrumbs / locating where a reaction sits', providing a clear use case. It does not explicitly mention when not to use it or direct to alternatives, but the context is sufficient for the agent to select it appropriately.

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