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

Annotations already declare readOnlyHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds real context beyond that: output is a diagram where the client supports it, the data is Kabuken-processed rather than raw FSA data, and taxonomy content carries a separate license. It omits behavior that matters for calling it, such as what happens at the limit boundary (truncation vs. error) or the response shape.

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 functional sentence is front-loaded, but it is followed by a parenthetical list of four near-synonyms (P&L structure, 損益の流れ, 収益構造, 損益計算書の構造) and then a long licensing/copyright block with URLs. The legal notice may be required, but it crowds out operational information within a single dense paragraph.

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 must characterize the return value, and it does so partially (diagram plus linkbase tree with an example arc). However, for a tool that returns a potentially large calculation tree governed by a limit parameter, the description never explains truncation, ordering, or what the amounts summary looks like.

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 100%, so all four parameters (doc_id, lang, limit, root_concept) are already documented in the schema, including the root-node-default behavior. The description adds no parameter-level detail beyond what the schema provides, so the 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 and resource: 'Returns the income flow ... of one filing' with concrete contents (revenue, cost lines, net result) and adds a second output, the XBRL calculation linkbase as a tree. The purpose is legible, but the two outputs (P&L flow vs. generic calculation tree) are blended into one sentence and no sibling tool is named to anchor the distinction.

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?

'of one filing' and the existence of root_concept imply per-document structural drill-down, but there is no explicit when-to-use or when-not guidance. Nothing tells the agent why it would pick this over get_financial_facts, get_segment_breakdown, or analyze_document for the same document.

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