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

No annotations are provided, so the description carries the burden. It discloses meaningful conditional behavior — that supplying portfolioId enriches each result with an isInPortfolio flag — and frames itself as a lookup step producing a securityId. It does not mention result ordering, pagination, or ambiguity handling when a query matches multiple securities, which is a gap for a search endpoint.

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?

Three tight sentences and no filler. The core purpose comes first, the workflow guidance second, and the conditional annotation behavior last — a well-ordered, front-loaded structure.

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 usefully names two returned fields (securityId, isInPortfolio) and the downstream consumer, which is enough for an agent to use the result correctly. It stops short of describing result shape, ranking, or what happens on zero matches, leaving a modest gap.

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 the schema already documents all three parameters (limit default 20, query format, portfolioId source). The description restates the portfolioId effect but adds no syntax or format detail beyond the schema, so 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 ('Search for securities') plus the accepted input domain (ticker, company name) and the covered asset classes. No sibling tool does security lookup, so it is easily distinguished from the many transaction/portfolio tools.

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 sequences the tool: 'Call this before create_investment_transaction to resolve a human-readable ticker into a securityId.' This tells the agent both when to use it and why, which is exactly the routing information a multi-step workflow needs.

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