lookup_symbol

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

No annotations are provided, so the description carries the behavioral burden. It discloses scope (stocks and ETFs) and a filtering lever, but says nothing about ambiguous multi-match results, ranking, or the fact that this is a side-effect-free read (though the output schema covers the return 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?

Three short sentences, front-loaded with the core action, then the when-to-call rule, then the coverage caveat. Nothing is wasted and no sentence restates the title or name.

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 an output schema present and all three parameters documented in the schema, the description supplies the essential entry-point guidance. The only gap is behavior on ambiguous or no-match queries, which is minor for a lookup tool.

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 coverage is 100%, so the baseline is 3, but the description adds intent beyond the schema by explaining why one would set asset_type='stock' — to exclude funds from results. That is real semantic value on top of the schema's mechanical enum listing.

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 precise verb and resource — resolve a company or fund name to its ticker symbol — so the transformation is unambiguous. It also declares coverage (stocks and ETFs), which separates it from the ETF-only siblings like etf_info and search_etfs.

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 an explicit trigger: 'Call this first whenever the user names a company instead of giving a ticker,' with a concrete example (Nvidia → NVDA). It does not state when-not-to-use or name a sibling alternative, 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.