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

With no annotations, the description carries the full behavioral burden, and it does add two genuinely useful facts: the return encoding (base64) and the 10 MB size cap. However, it is silent on what happens when an attachment exceeds the cap, permission/auth requirements, and failure modes.

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 tight sentence with the return format and size limit front-loaded. No wasted words, though it is arguably under-specified rather than truly concise.

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 one-parameter read tool with no output schema, the description covers the essentials of what comes back and its size bound, but omits how to obtain the ID and the behavior on limit violations or errors.

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 0% and the single attachment_id parameter has an unusual composite pattern (^\d+:\d+$) that is nowhere explained. The description says nothing about the parameter, so it fails to compensate for the coverage gap.

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') and resource ('message attachment'), and the parenthetical clarifies that raw base64 bytes are returned rather than metadata. It is distinguishable from get_message by the 'attachment' resource, though it never explicitly contrasts the two siblings.

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?

No guidance on when to use this versus get_message, and no hint that the attachment_id must first be discovered via get_message. The agent is left to infer the retrieval workflow entirely.

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?

With no annotations, the description carries the full burden and does disclose one valuable non-obvious trait: reading does not flip an unread message to read status. It omits other behavioral facts such as what happens for an invalid or missing id, permission requirements, or error behavior.

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 front-loaded sentence with no filler. The critical behavioral constraint (no read-status change) is stated inline rather than buried, so nothing needs trimming or reordering.

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 one-parameter read tool with no output schema, the description covers the key side-effect concern but leaves the parameter, failure modes, and its boundary with get_attachment undefined. Adequate but with clear gaps for an agent to call it confidently.

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 single id parameter has no description in the schema (0% coverage) and the description says nothing about it. The schema's numeric pattern hints at format, but the description adds no meaning about which identifier is expected or where it comes from.

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 (Read) and resource (full text and attachment metadata of a message), which is clear and unambiguous. It does not, however, distinguish itself from the sibling get_attachment, whose scope partially overlaps with 'attachment metadata', nor from list_messages.

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?

There is no explicit guidance on when to use this tool versus list_messages or get_attachment. The phrase 'including for unread messages' hints at a use case but never states conditions, exclusions, or the alternative to pick for other needs.

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?

With no annotations, the description carries the full behavioral burden. It usefully discloses the returned field set (previews, unread state, attachment names) and the 'received' scope, but says nothing about pagination, ordering, limit behavior, or the read-only/safe nature of the call.

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 front-loaded sentence with no filler; the returned-field enumeration is efficient. It is appropriately sized for a one-parameter list tool.

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 listing tool with one optional parameter and no output schema, the description covers what the tool is and roughly what it returns. It is incomplete on the things an agent needs to call it correctly — the meaning/effect of 'limit' and pagination behavior.

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 0% for the single 'limit' parameter, and the description never mentions it. Bounds and default exist only as bare schema constraints (1–100, default 30), so the description does not compensate for the missing pagination semantics.

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 ('List') and resource ('received Skolemelding messages') plus the returned fields (previews, unread state, attachment names). It is implicitly distinguishable from get_message/get_attachment by being a bulk listing, but it never names those siblings or contrasts itself with them.

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 — an agent can infer this is the inbox-browse step before calling get_message, but the description gives no explicit when-to-use, no exclusions, and no mention of the alternatives.

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