List categories

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

Annotations already declare readOnly, idempotent, non-destructive, open-world, so the safety profile is covered. The description adds real substance beyond that: a bounded result set of 10 categories, budgets broken out by fixed price vs hourly and by the four freelancer levels, and per-currency values — information that matters because no output schema exists. It stops short of noting any rate limits or whether budgets are cached/updated, which keeps it off a 5.

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-line summary sentence up front, followed by a compact expansion that stays on the resource itself. There is no filler, no repeated title restatement, and the most important identity/cardinality fact is front-loaded.

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 carries the burden of explaining return values, and it does: categories, subcategories, and median budgets by pricing model, freelancer level, and currency. Combined with a single optional, fully documented enum parameter and read-only annotations, an agent has everything needed to call it correctly.

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 would be 3, but the description earns above baseline by clarifying that the currency applies to the median budgets and that values are supplied 'in the currency asked for' — reinforcing the enum's meaning and reminding the agent the default is GBP via the schema. It adds interpretation rather than merely restating the property.

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 states a specific resource (PeoplePerHour project categories, subcategories, and median budgets) and its exact cardinality ('The 10 project categories'). It also distinguishes itself from sibling search tools by explaining that 'category is the slug search_projects and save_search take', so an agent can see how it relates to them rather than confusing it with search_projects itself.

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?

It gives a concrete use case ('a guide when pricing a proposal or a project') and positions itself as the reference source whose slugs feed search_projects and save_search. What is missing is an explicit exclusion or sequencing rule (e.g. 'call this before search_projects to resolve a category name'), but the context for when to reach for it is clear.

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