list_stocksFull list of covered Japanese listed securities (equities, ETFs and REITs; see assetType; preferred and other class shares have isPreferredShare: true). Large response: costs 100 tokens, so prefer search_company for a single lookup. 全上場銘柄リスト（株式・ETF・REIT を含む。assetType で判別。優先株・種類株は isPreferredShare が true）。レスポンスが大きく、トークン消費 100。単発の検索には search_company を。
| Name | Required | Description | Default |
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Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, so safety is covered; the description adds genuinely new behavioral context by quantifying the response cost (100 tokens) and warning that the payload is large. It does not describe ordering, record counts, or whether results are cached/paginated, which would complete the picture.
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 English sentence is front-loaded with scope, then cost, then the alternative — exactly the right order. The full Japanese restatement doubles the length for an agent that reads either language, which is mild redundancy rather than noise.
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 parameters and no output schema, the description carries the burden of explaining what comes back, and it does: instrument coverage, the assetType discriminator, and the preferred-share flag. Missing is any sense of scale (how many securities) or ordering, which matters for a large fixed payload.
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 tool takes zero parameters, so the baseline is 4. The description's references to assetType and isPreferredShare describe response fields to filter on client-side rather than input parameters, which is useful but slightly off-dimension.
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 ("Full list of covered Japanese listed securities") and enumerates the covered instrument types (equities, ETFs, REITs, preferred shares) with the flag that identifies them. An agent can distinguish this from search_company or list_etfs 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?
Explicitly tells the agent to prefer search_company for a single lookup, giving a concrete when-not condition tied to response cost. It does not mention other plausible alternatives such as screen_stocks or run_screener_preset, so routing against the full sibling set is only partially covered.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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