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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered; the description adds real value beyond them by disclosing that option delta appears only when the broker reports it, and that apps supporting MCP Apps get an interactive panel while every call still returns a text summary plus a botspot.trade link. It omits auth/prerequisite behavior, which matters for a tool that depends on broker connectivity.

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 definition is front-loaded with the questions it answers and the payload, with no filler sentences. The parenthetical about option delta and the dual rendering note are dense but each earns its place; slightly tighter phrasing would read better but nothing is truly wasted.

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 does the necessary work of listing return values, and the dual app/text rendering is spelled out. The remaining gaps are the unexplained brokerCredentialId parameter and the absence of any statement about what happens when no position exists or the broker is disconnected.

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% for two parameters, so the description carries the full burden. It implies the symbol is a ticker via the TSLA examples but never states accepted forms, and it does not mention brokerCredentialId at all — an agent cannot learn from the description that credential selection exists or how to supply it.

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 first clause states the exact question the tool answers and the resource it resolves (one symbol's position), then enumerates the returned fields: value, unrealized P&L, shares and average cost, exposure in share-equivalents, and a payoff chart. An agent can distinguish this from siblings like show_holdings (portfolio-wide) or show_option_payoff (payoff only) without opening a 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?

Usage is grounded in concrete example questions and in the scoping phrase 'for a stock symbol or an options underlying', which makes clear this is a single-symbol lookup. It stops short of naming an alternative or stating when not to use it (e.g. for a whole portfolio, use show_holdings), so the guidance is clear but not routing.

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