select_symbol

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

Annotations already declare this is a mutating, open-world operation that is not destructive, so the safety profile is covered structurally. The description contributes the non-obvious consequence that the symbol is added so history can download, but does not state what happens when the symbol already exists, what removal does to stored history, or whether the watchlist persists across sessions.

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?

One front-loaded sentence with no filler. It is short to the point of under-specification rather than bloated, so the structure is clean but the content is thin.

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?

For a two-parameter mutation tool with no output schema and zero schema descriptions, the description should explain the add/remove switch and the symbol format. It covers only the intent, leaving the invocation mechanics to guesswork.

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 carry the parameter burden and it does not. It never explains that 'visible=true' adds the symbol and 'visible=false' removes it, nor does it say what format 'symbol' takes (ticker exchange suffix, case, etc.), which is exactly the mapping an agent needs.

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 names a concrete verb pair and resource ('Add or remove a symbol in Market Watch') and adds an end goal ('so history can download'), which distinguishes it from read-only siblings like list_symbols and symbol_info. However, the dual add/remove behavior is not tied to any parameter, leaving the core action ambiguous.

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?

No when-to-use guidance and no alternatives named. An agent cannot tell from the description whether this is a prerequisite for probe_history, extend_history, or history_coverage, even though the 'so history can download' clause hints at a workflow without stating it.

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