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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds genuine behavioral context beyond that: grade columns vary by set, so a vintage set may carry different grade tiers than a modern one, which prepares the agent for a variable-shaped response.

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?

Two sentences, front-loaded with what the tool returns, then how to obtain the required identifiers. Efficient with no filler, though the parenthetical about grade columns is slightly dense.

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?

An output schema exists, so return values need no explanation. The description covers purpose, identifier sourcing across three required params, and response variability. Complete enough for a read-only three-param lookup; only the lack of any explicit exclusion guidance keeps it from a 5.

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 relational meaning the schema does not: category_path, set_path and set_id must be combined to identify a set, and it names where each value comes from. That is real added value over the isolated field descriptions.

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 ('One PSA Price Guide set's full grade-by-grade price table') and makes the scope explicit ('every card in the set with PSA's own formatted price per grade column'). It is clearly distinguishable from siblings psa_price_guide_search (which finds sets) and psa_price_guide_categories (which browses categories).

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 tells the agent how to source the identifiers: 'use the matching fields from a psa_price_guide_search result, or category_path from psa_price_guide_categories combined with a set_path/set_id found by browsing PSA's own category page.' This routes the agent through the correct sibling tools, though it doesn't state an explicit when-not-to-use condition.

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