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

Goes well beyond the readOnlyHint annotation: it discloses error semantics (404 for unknown symbol, 400 with valid values for unknown indicator), the return shape (one row per trading day, ordered by date, column set varying by indicator), and the empty-range behavior. Auth requirement is also stated explicitly.

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?

Front-loaded with the one-line purpose, then prerequisite, then error/return behavior, then auth – a logical order with no filler. The return-shape sentence is partially redundant given an output schema exists, which is the only real trim opportunity.

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 4-required-param read tool with an output schema, the description still covers the prerequisite dependency, both failure modes, ordering, and auth, so an agent can call it correctly on the first attempt. Nothing material is missing.

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%, including the list_options cross-references and the YYYY-MM-DD inclusive semantics, so the schema already carries parameter meaning. The description adds only the aggregate notion of a date range and per-row date ordering, which is not materially beyond the schema. 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?

Names a specific verb ("Fetch"), a specific resource ("historical technical-indicator series"), and the scoping axes (symbol, date range). This is clearly distinguishable from siblings like get_company_snapshot or get_aftermarket_data 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?

Gives a concrete prerequisite: call list_options("technical_indicators") first to obtain valid indicator names, which prevents a predictable 400. It stops short of stating when-not-to-use this tool or naming an alternative series endpoint, so it is clear context without exclusions.

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