control_chain

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

The description discloses important behavioral traits beyond the readOnly/openWorld/idempotent annotations: it abstains (abstained=True) when no verified edge exists, never fabricates chains from sub-50% or unclassified stakes, and explains per-step fields like percent_of_class, 13D accession, and institutional_value_usd (null for ~25% of issuers). This is rich, honest behavioral context.

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 well-structured with a clear first sentence, a scoped details paragraph, and concrete examples. It is longer than strictly necessary, but each section earns its place by adding behavioral or usage context. The only minor issue is that some statistics (20 of 825, 97 of 825) could be tightened without loss.

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 complexity and the presence of an output schema, the description is nearly complete: it covers abstention behavior, direction semantics, field meanings, and materiality ranking. The missing explicit explanation of `max_hops` is the main gap, but the examples and scope discussion provide enough context for correct invocation.

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 0%, so the description must compensate. It thoroughly explains the `direction` parameter and provides examples that clarify `company`, but it never explicitly describes `max_hops` or its default value, even though the multi-hop discussion implies its existence. Partial compensation, but not complete for all three parameters.

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 'Trace the transitive >=50% ownership control chain through a public issuer,' which names a specific verb (trace), a resource (ownership control chain), and a clear threshold (>=50%). It also defines direction='up' vs 'down' and gives concrete examples, distinguishing this from sibling graph tools like influence_map or ownership_snapshot.

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 'Scope, precisely' paragraph gives clear context: single-hop control is general-purpose, multi-hop chains are a small-cap governance signal, and most large caps have no >=50% holder and will abstain. This effectively tells the agent when to use the tool, but it does not explicitly name alternative tools or state when-not-to-use in favor of a sibling, so it stops short of a 5.

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