substack-saved-mcp

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search_saved_posts

Search saved Substack posts by full-text across title, excerpt, author, publication, and content, with filters for date, audience, and read state.

Instructions

Perform full-text FTS5 search across cached saved posts.

Searches title, excerpt, publication name, author, and content text (content is only present for posts fetched via get_post_content). query uses SQLite FTS5 syntax; a malformed query falls back to a substring match. Date filters take ISO 8601 strings (e.g. "2026-01-31"). Allows filtering by publication name, audience tier (see list_audiences for cached values, e.g. "everyone", "only_paid"), original post date (published_at), saved date (saved_at), and read_state ('unread', 'in_progress', 'finished', 'unfinished' (unread + in_progress), or 'started' — a post is 'finished' once its high-water reading progress crosses a threshold, default 0.95).

Input Schema

TableJSON Schema

Name	Required	Description	Default
`limit`	No
`query`	Yes
`audience`	No
`read_state`	No
`publication`	No
`saved_after`	No
`saved_before`	No
`published_after`	No
`published_before`	No

Output Schema

TableJSON Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed7 schema fields changedv0.3.1Aug 22, 2026

addedInput schema / properties / read_state

Added value: +{
+  "anyOf": [
+    {
+      "type": "string"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null
+}

addedOutput schema / properties / result / items / properties / is_fully_read
```
Added value: +{
+  "readOnly": true,
+  "type": "boolean"
+}
```
addedOutput schema / properties / result / items / properties / is_viewed
```
Added value: +{
+  "default": 0,
+  "type": "integer"
+}
```

addedOutput schema / properties / result / items / properties / max_read_progress

Added value: +{
+  "anyOf": [
+    {
+      "type": "number"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null
+}

addedOutput schema / properties / result / items / properties / minutes_remaining

Added value: +{
+  "anyOf": [
+    {
+      "type": "integer"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "readOnly": true
+}

addedOutput schema / properties / result / items / properties / read_progress

Added value: +{
+  "anyOf": [
+    {
+      "type": "number"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null
+}

changedOutput schema / properties / result / items / required

Previous value: -[
-  "url",
-  "title",
-  "publication_name"
-]New value: +[
+  "url",
+  "title",
+  "publication_name",
+  "is_fully_read",
+  "minutes_remaining"
+]

First observedv0.1.0Aug 2, 2026

TDQS

A4.4/5.0

Behavior4/5

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

No annotations exist, so the description carries the burden, and it delivers: malformed FTS5 queries fall back to substring matching, date inputs are ISO 8601, and 'finished' status is defined by a reading-progress threshold defaulting to 0.95. It omits result ordering, pagination behavior, and confirmation of read-only/side-effect profile.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The core operation is front-loaded and most sentences carry substantive information. It is somewhat long and the read_state parenthetical is awkwardly worded, but there is little outright filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With 9 parameters, no annotations, and an output schema that handles return values, the description supplies the semantic detail an agent needs for nearly every filter plus a key behavioral caveat. Missing ordering and pagination guidance keeps it from fully complete.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters5/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description must compensate and largely does: it explains query syntax plus fallback, enumerates read_state values with definitions, distinguishes published_at from saved_at, gives audience examples, and specifies ISO 8601 for all date filters. Only 'limit' is left without descriptive meaning, but its default is visible in the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Perform full-text FTS5 search across cached saved posts') and names the searched fields (title, excerpt, publication, author, content). This is distinguishable from search_saved_notes and list_saved_posts by resource and mechanism alone.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives real usage context: it routes the agent to list_audiences for valid audience values and warns that content text is only present for posts fetched via get_post_content, implying a prerequisite. It stops short of stating when to prefer list_saved_posts over this search or when not to use it.

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

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