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

Annotations already declare readOnlyHint=true and openWorldHint=false, and the description adds genuinely new behavior: values are fetched fresh from Home Assistant rather than cached, and attributes are a filtered subset rather than the raw attribute dict. It does not say what happens when an entity_id is unknown, which is the one remaining behavioral gap.

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 short sentences, front-loaded with the core purpose and followed by meaningful qualifications about freshness and attribute filtering. Slightly padded by the parenthetical climate example, but nothing is genuinely wasteful.

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 structure needn't be described; the description instead covers the two things the schema cannot express, data freshness and attribute filtering. Combined with readOnly annotations, that is sufficient for an agent to call this 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?

Only one parameter and schema coverage is 100%; the schema already carries the pattern, example ('climate.hvac') and the search_entities discovery hint. The description adds nothing parameter-specific, so 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?

States a specific verb ('Get'), resource ('live state of one entity') and the payload contents (area, device, relevant attributes). It is clearly narrower in scope than sibling tools like search_entities and list_areas, though it never names those siblings to contrast explicitly.

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 only implied: it tells you the state is read fresh and attributes are domain-filtered, so an agent can infer it is for inspecting a known entity. There is no explicit 'use this instead of X when Y' guidance, and the pointer to search_entities lives only in the schema description, not here.

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

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

readOnlyHint=true and openWorldHint=false already declare this as a safe, closed-domain read, so the safety profile is covered. The description adds only that each area comes back with its entity count and that its identifiers are reusable downstream; it says nothing about empty homes, unnamed areas, or ordering.

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 short sentences, zero filler, with the resource definition first and the follow-on usage hint second. Every clause carries information the agent needs.

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 parameters, an output schema, and read-only annotations, the description covers purpose and downstream usage adequately. Minor gap: it doesn't mention what happens when no areas exist or how the two identifier forms differ in practice.

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?

The tool takes no parameters, so there is nothing to disambiguate and the baseline of 4 applies. The description correctly focuses on the return fields (`area_id`, `name`) that serve as inputs to other tools.

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 ("List all areas") and disambiguates the term with "(rooms/zones) of the home." It also states what each result carries (entity counts), so the agent knows exactly what it gets 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?

Explicitly routes the agent into the workflow: take `area_id` or `name` from here and pass it to search_entities. There are no exclusions or "don't use this when" cases, but for a zero-arg enumeration tool the intended context is clear.

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

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds real value beyond that: the returned fields (entity_id, name, state, area) and the result ordering ('best matches first'). It does not mention limit/pagination behavior or what happens when nothing matches, which is why it stops short of 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?

Three short lines, front-loaded with purpose, followed by the workflow hint and the return shape. No filler sentences and nothing repeated from the schema.

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?

Annotations cover read-safety, an output schema covers return structure, and the schema fully documents all four parameters. The description supplies exactly the missing piece — the discovery-then-detail workflow with get_entity_state — so 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 description coverage is 100%, and the schema already documents query matching semantics, area, domain, and limit with a max of 100. The description adds no parameter-level detail (no note that an empty query lists everything, no guidance on combining filters), so this is the baseline for a fully documented schema.

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 ('Find Home Assistant entities and their current states') and immediately distinguishes itself from the sibling read tool by naming get_entity_state for details. An agent can tell what this does and how it differs from adjacent tools 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?

Explicitly says 'Use this first to discover entity_ids, then call get_entity_state for details', which gives both the ordering rule and the named alternative. The condition that selects this tool versus get_entity_state is unambiguous.

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