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

Annotations already declare readOnly, idempotent, non-destructive behavior, so the description's job is lighter; it still adds two genuinely useful behavioral facts the annotations do not carry: the normalization rules (case- and whitespace-insensitive) and a cost of 1 credit. It stops short of stating the return type (presumably a boolean), which is the only behavior an agent must still guess.

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?

A single sentence front-loads the operation, the exact algorithm, and the normalization rules, with the credit cost appended in parentheses. There is no filler or redundancy.

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 simple two-string predicate with full schema coverage and complete safety annotations, the definition covers purpose, semantics, normalization, and cost. The only missing piece an agent might want is the shape of the response (boolean vs. structured result), which no output schema supplies.

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%, so word1 and word2 are already documented as required strings with no units or defaults. The description adds only the comparison semantics ('ignoring case and whitespace'), which applies to both inputs — helpful but minimal beyond the schema, so the baseline 3 holds.

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 gives a specific verb and resource ('Checks if two words are anagrams') and then defines the exact comparison rule (same characters, same frequencies), so an agent can distinguish it from neighbors like is_palindrome or is_rotation without opening the 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?

The purpose makes the applicable situation obvious, but there is no explicit when-to-use/when-not-to-use statement and no routing to or from sibling tools such as is_palindrome or text_stats. Usage is implied rather than stated.

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