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

Annotations already declare read-only/idempotent/non-destructive, but the description adds real behavioral context beyond them: it is a derived view over existing substrates, each substrate 'keeps its own gating,' the free tier 'leaks no paid fields,' the capability array carries active links only and takes no widening parameter, and the three arrays are 'never merged' because they are different kinds of claim.

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-loads the core purpose in the first clause before diving into the three-array breakdown, and every subsequent sentence carries meaning (array contents, distinctions, alternatives). It is dense and long, but not padded with redundant restatement.

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?

With no output schema, the description fully describes the return shape (three named arrays with their per-item fields), the gating/visibility model, and the alternatives for related queries. An agent has everything needed to call it correctly and interpret results.

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?

Only one parameter and schema coverage is 100%, so the schema already documents the event_id semantics fully. The description adds a little framing ('the event's neighbourhood as the corpus now stands') and 'Pass event_id,' but no format or syntax beyond the schema. Baseline 3 applies.

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?

States a specific verb (assemble) and resource (the stack journey for one event), then enumerates the three arrays returned. It explicitly names sibling tools (get_threads, traverse_coordination, get_capability_links) so an agent can distinguish this tool from them without opening any schema.

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?

Gives explicit when-to-use alternatives: 'For the material layer alone, use get_threads; for the directed multi-hop coordination lineage between events, use traverse_coordination,' and 'for retired memberships, use get_capability_links with include_retired.' These are concrete routing conditions with named alternatives.

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